The Best Way to Power Your Railway | Third Rail vs. Overhead Wire 

This video a remake of a previous video incorporating viewer feedback and fully revamping the visuals and rewriting the script (for more details, see my recent community post). Please enjoy and consider sharing!

One day there will be a train management sim where you have to decide what type of electrification you use only to curse yourself that you need to adapt your new trains to run on old electrification standards.

It's high voltages that are more efficient at transmitting power over long distances, rather than this being something inherent about AC. In fact, DC is actually more efficient at transmitting power than AC, but this is overshadowed by the difference between voltages - this is why a lot of modern high voltage power links use DC. The reason that high voltages are traditionally associated with AC though is that up until relatively recently, it was just impossible to handle high voltage DC affordably and practically. AC can very easily be changed in voltage using a transformer, whereas DC needs modern power electronics to change the voltage. So why is high voltage more efficient? Well, P=IV tells you that for a given amount of power that needs to be delivered, if your voltage increases, current will decrease (I = P / V). Now if we take R to mean the resistance of the *wire* rather than the load, P = I^2 R tells us that for a given value of current, power loss in the wire will be greater, in fact proportional to the square of the current. So increasing the voltage dramatically reduces power lost. This is why power transmission lines tend to be very high voltage. OK, so why isn't third rail high voltage if it's more efficient? Simple - because it's close to the ground, the return path, and potentially humans, it's neither safe nor practical to make it much higher voltage than maybe 1000V or so. Most third rail I know of is in about the 500-750V range. So why build third rail in the first place if it's so much less efficient? Well, this comes down to another difficulty of AC vs DC. In the early days of rail electrification, there was no practical way to convert from AC to DC on a train. Why would you want to do this? Again in these early days, AC motors could only be made to go at one speed which was governed by the frequency of the AC power. This is not good for a train, so instead they used DC motors, which are more expensive to maintain but would allow for easy changing of speed by doing things like switching resistors in and out of the circuit. So at this point your only choice is DC distribution - and with DC distribution your only choice at this point was low voltage. The Germans actually came up with a clever way around this - it turns out that low frequency AC can be used to drive traditional DC motors, with a bit of modification. So they used low frequency AC to power their trains, 15kV AC @ 16.7Hz. What's the trade-off here? With lower frequency AC you need much larger transformers to convert the voltage. This trade-off was considered worth it. But in other countries, they went with relatively low voltage DC transmission, either through third rail or overhead lines. Of course, they were often only building very urban electrification systems at first, so the power losses didn't matter much. This is also why they still build new metro systems with third rail - you're just over such a small area that having to have more substations and more power loss is not worth the hassle of going with AC. But for long-distance lines, the power losses start to get significant. Then around the 50s, technology like mercury arc rectifiers, soon after giving way to solid state rectifiers of various sorts, could now be fitted on trains. This would allow AC to DC conversion to happen on trains. This means you can now have high voltage efficient transmission at normal mains frequencies, convert it down to low voltage for your motors, and rectify to DC. This is about when the 25kV AC @ 50Hz (or 60Hz depending on the local mains frequency) standard emerged for overhead wires, a standard used across large parts of the world to this day. Of course many countries still retain their legacy systems as well, and perhaps only use 25kV on new high speed lines, if at all. But it's heavily used in large parts of France and Britain, and many places that didn't have a serious electrification programme until a significant time after WWII. As far as I know after the technology was proven in Britain and France, no country has chosen anything else for a completely new-build electrification system for a long-distance rail network where there hasn't been a need for compatibility with some existing electrification. What else has changed? Remember I said that DC motors are harder to maintain than AC ones? Well, advances in power electronics in the 1990s have allowed DC motors in trains to give way to AC motors. This basically involves using power electronics to change the frequency of the AC as required to change the speed of the motors. Nowadays most trains, even ones designed to run on DC power, will have AC motors; obviously the DC will be converted via power electronics to AC to power the motors. Many trains since the early 90s and most trains since the 2000s have been built like this.

If anyone else is curious like I was, the reason why the pantographs don't ruin the wires and themselves with friction when trains are going at such high speeds is the contact point uses graphite. Graphite is both a solid lubricant and electrical conductor. When it wears down they simply replace the contact point on the pantograph and the wires above are just fine.

One of the main benefits of electrification (vs systems where the power is generated on board the train), regardless of the mode of collection. is the ability to adapt the power supply to different sources of generation without having to change your fleet of rolling stock. You can switch to cleaner, more efficient technologies as they come along, and the railways and transit providers are unaffected. You can contrast this with the costs North American freight railways have had to bear as new pollution standards for diesels have been implemented. New standards mean newer, more expensive locomotives.

This may be a bit of a controversial view, but I actually like how overhead wires look, along with the pylons. If done right, it can give a sort of futuristic feel to a railway.

I work for the Washington DC Metro. I just wanted to point out a few details about 3rd rail you missed. 1. The main reasons 3rd rail switches sides is to separate sections so they can be shut off in individual segments instead of the whole line, also it evens out the wear on collector shoe. 2. On a bottom contact system the top and sides are still live as it's a solid piece of metal, also the bottom and sides of the third rail are the most likely places to accidentally touch with your foot, not the top. 3. For inclement weather there is heater tape on the rails. Also we have special deicer flatcars that have insulated scrapers to scrape ice off the 3rd rail and spray nozzles for glycol antifreeze. Additionally in extreme conditions the revenue cars can also be outfitted with glycol sprayers. 4. In the yards there is 3rd rail. However inside the railcar shops there is something called a "stinger", which is basically a 750 volt jumper cables hanging from a track on the ceiling. It's got a clamp on the end that a mechanic wearing insulated gloves will attach to a collector shoe. This is probably what they're talking about for the Chinese metro yards.

I've seen the MBTA blue line change modes from third rail to catenary! It happens at airport station

Interesting. I like the idea of using third rail below ground and then swapping aboveground to make it safer for people. Also the idea of having the power lines oscillate to spread wear out. That's one of those subtle little design features that I'm sure was a big "oh duh" moment when someone came up with it.

You missed one of the best examples of a train system that uses both overhead wiring and third rail on the same service: The New Haven Line of Metro North Railroad, which serves New York City and its Northern suburbs including into Connecticut. Running from Grand Central Terminal in New York City, the New Haven Line uses third rail power at 700V DC to just outside NYC at Pelham, NY, where it switches to overhead line at 12.5kV AC. Just a few miles further at New Rochelle, NY, the line becomes shared with Amtrak long distance services joining it from a line from Penn Station to the South, which also use AC overhead electricity - Metro North and Amtrak services share the rest of the line from New Rochelle NY to New Haven, Connecticut using said overhead line all the way.

Technically Catenary refers only to the top of the 2/3 wires in a typical OHLE system due to the shape it follows. The wire that the pantograph actually touches is called the contact wire (and droppers connect the 2) When there is only 1 wire as in a tram system its generally referred to as a trolly wire regardless of whether pantographs or trolly poles are used (or both as per Toronto)

10:40 this approach of using catenary in the train yard to protect the workers is used on the Bucharest Metro system in Romania. On normal service, the Bucharest Metro uses third rail power at 750V DC, while on train yard it is used low-power overhead lines at 230V DC, where the maximum speed is at 15 kmh!

I'm a Driver Trainer for Thameslink (and Great Northern), so get to experience both AC & DC. Personally AC is better, if you're going Rapid Transit. You just get more power on tap from the 25kv AC than the 750v DC. The Difference is so noticeable from the Cab... Rigid Catenary works well for lower tunnels etc. AC is more pricey overall.

Rigid Catenary in urban tunnels with regular catenary in the open seems like the best overall option to me. Does anyone know what Crossrail uses in tunnels? It seems to be rigid catenary but with catenary poles? Odd

Interesting fact: only third rail subway lines have their well known smell because the graphite from the contact shoes wear out and the poor ventilation on sublevel lines create the distinctive smell

It's basically the battle between the 'coat-hanger and knitting' or the 'stabiliser rail'. To be honest, nowadays it's easy enough to have trains that can do both. A lot of UK trains either have both fitted, or are designed so that the other system can be retrofitted relatively easily.

Watching this as a Chicagoan I didn't realize how unusual it is that Chicago has an entirely uncovered top contact third rail for the entirety of the 'L' , which even includes a lot of grade crossings on the Brown, Purple, Pink and Yellow lines.

It may just be me but I like the appearance of the catenary. In Germany the Green Catenary poles have become a Staple and it's hard to find anyone who actually considers them obtrusive

Here in cologne the Stadtbahn uses 750/800V overhead wire, and what that enables is that some parts of the tracks are shared with freight trains as overhead wire is the standard on nearly all tracks in Germany. Only thing that had to be done was changing the voltage when the new lines were opened

Fun fact: London's old trams used to use a hybrid system (3rd rail and overhead) you can still see the remains of the 3rd rail in the kingsway tram tunnel

Great video. Kudos for mentioning mentioning the UK southern rail network (you need to make a video on that a some point!) and Thameslink. Thameslink is interesting because it also uses rigid catenary in the central section around Farringdon/Blackfriars. One question your video threw up for me is WHY the Underground uses a 4 rail system when 3 rails works perfectly fine for everyone else. After a quick search on Google, apparently it's because the isolated traction current return allowed a train's position to be detected using DC track circuits (which I think can now be done with 3rd rail systems but couldn't back when the Underground was first electrified), and reduced any earth leakage currents that could affect service pipes, telephone cables, or cast iron tunnel liners.

Pre-60s trams extensively used centre-aligned 3rd rail in many cities around the world, fun fact

This electric rail system has been interesting me since my childhood, and your video has given me the essential information to understand its work procedures

The Hamburg S Bahn also has a branch where the trains run on the regular DB network with overhead wire with the rest od the system being equipped with side contact third rail

In Spain rigid catenary is also used on new mainline urban tunnels, even for high speed lines, although obviously they run at not more than 100/120 kmh. A good example is the newly opened (1/07/2022) Chamartin-Atocha-Torrejon de Velasco HSL, wich on its urban underground section runs with rigid catenary. It is said that for this kind of underground low speed infrastructure, it has lower maintenance and installation costs, and it also occupies very little space.

Great shot of that Eurostar train passing through Stratford International Station (I was there last week to see the same for myself!!) That's going from London to Paris or Brussels. The centre (island) platform serves domestic "High Speed" services, the outer platforms are not used so much but are available for when required eg London 2012 Olympics. These High Speed trains use overhead power lines when on the faster lines and 3rd rail power track on the traditional railway routes, with swap overs whilst stopped at Ashford or Ebbsfleet stations (depending on route in service). The changeover takes seconds to complete and passengers don't notice a thing - except the change in speed of travel afterwards (of course). (Similar to Thamslink trains as you mentioned). As for weather, a few years ago when there an exceptionally cold and snowy snap in Southern England there were massive problems with freezing rain and ice on the 3rd rails, indeeed one train broke down due to power supply flactuations damaging the onboard electrics, and I got stranded for over an hour due to loss of power. (Near Ramsgate in Kent).

Increasing voltage is more important than the choice of AC or DC. And higher voltages are more practical with AC because of simpler switching and transformation, although modern electronics is changing that. Trains mostly use 25kV single phase AC, which can be difficult to take from three phase distribution systems, especially where the train loads are large compared with other loads on the system. It is possible to use three phase power by using two catenary wires and the rails. One very old example of this is La Rhune in SW France.

Excellent overview. To a La Presse columnist who superciliously complained that the wiring of the REM on the Champlain bridge was “visual pollution,” I’d say I’d be much much, more worried about the gaseous, respiratory pollution generated by all the SUV’s and “light” trucks on the bridge.

9:32 I’d actually like to correct you just here. Overhead wires can actually work for tall freight loads if done correctly. Indian Railways operates double stack trains and they built their wires high enough where the containers don’t interfere with the wires. As a result, all of their electric locomotives have bigger pantographs that can reach the really high wires. India also stacks their containers a little higher than in North America because they just double stack conventional flat cars whereas in North America we have special train cars that allow the containers to be mounted near wheel level. That’s the only thing I’d like to correct you on. Other than that this video explained in really good detail about electrification

There are also some diesel trains fitted with pantographs/shoes so they can run on electric power on portions of their routes. This is becoming pretty popular in the UK with new trains like the class 755, 800, 802 and 88. Also there's the class 768/769 which were converted from electric only trains into tri-mode diesel, 3rd rail and OHL trains.

The reason why the London's Underground rail system has four rails is for stray current return. This fourth rail mitigates the problem of electrolosis due to the fact the stray electrical current will corrode nearby steel pipes and structures. The fourth rail has a low impedance return current path back to the power source, or generator. This keeps all metal structures in the vicinity from rusting.This also aids in tripping the circuit breakers faster because of higher currents, all to prevent electrical shocks.

So I'm assuming that dual mode catenary third/rail works decently well since the AC from the catenary needs to be rectified into DC anyway before the motor controller reconverts into 3-phase AC at the right frequency for the speed the train is currently at So putting the third rail DC at the same voltage as the output of the rectifier means that the only additional equipment you need is a third rail shoe

in Vienna you have a couple electric busses which run on battery, but if they need charging, they can do that with raising a pantograph towards tram overhead wires :D ... I believe there is like one line that uses those there :)

One thing with the choice between AC and DC is the need of on board transformer with an AC system, which tend to be heavy. Sometimes the weight is a good thing, for example heavy electric locomotives, which need the weight to have enough adhesion. On the other hand, light rail systems benefit from being... well, light.

Surprisingly, there have been some new grade crossings with third rail built in Europe, or rather lines with grade crossings that got converted to third rail. Oslo's Line 1 was an interurban style line with overhead wire and grade crossings but it got converted to metro standard third rail, keeping the crossing. And in Rotterdam, the metro line to the Hague was converted from a mainline railway, mostly keeping the overhead electrification but the third rail does extend across one grade crossing on the Rotterdam end.

And my personal favourite is Detroit's trams that are overhead wire + battery to power them during a couple of sections with no overhead wires.

Thank you Mr Transit for this video

Thank you for defining catenary and pantograph! Your lay viewers appreciate it!

Not only Thameslink but also Overground & Southern services to Watford switch between overhead and third rail when crossing through London - in fact, the Overground does it on three different parts of the network

What Reece forgot to mention, is the new generation of passenger trains being the hydrogen fuel/battery urban metro, regional and inter-regional trains like the Alstom Coradia iLint which has been in commercial services in Europe for 5 years, the Stadler Wink, Stadler GTW and Siemens Mireo Plus H. Alstom has launched for France's SNCF regional rail services. the Alstom Coradia Polyvalent H2 being 4 carriage 218 seat electric and hydrogen fuel/battery regional and inter-regional passenger rail services.

A lot of the south eastern services in the UK are starting to hit the limits of what is possible on 3rd rail electrification, just because of the sheer number of services being run. It has been vaguely floated that the 3rd rail will be replaced by OLE at some point in the future, which seems likely. Fortunately, the fact that dual mode units are so prevalent helps considerably if we decide to do it more gradually, such as for electrification in many places. (Funnily enough, diesel/electric bi-modes seem to actually result in more electrification, rather than an excuse to avoid it)

The Sydney light rail operates both the Alstom third rail and also overhead, it changes modes at Town Hall station. There's also a light rail in Newcastle (Aus) that I think operates by battery, and charges via overheads as it stops at each station.

In the southern part of england the timetable is actually designed with the third rail gaps in mind, there are certain locations trains cannot stop and more than x trains an hour cannot pass through incase of delays, for instance GTR Southern 4 car units cannot use certain platforms because of the gap in the third rails

Thanks RM! Love all of your videos but especially love these educational breakdowns. As a transportation geek in training I found this extremely helpful 🙏🙏🙏

Sofia, Bulgaria - M3 line also uses "rigid catenary" in tunnels, and a classic wire at the open section (near and at depo).

It would be cool to see Seattle raise its platforms and use overhead wire powered heavy rail like Cleveland used for its red line

The amount of power you can get on low voltage DC systems is limited to about 2MW because the currents get so massive. OK UK Southern region has stretched this to 4MW in parts of the network at the expense of substation little over a mile apart and trains which automatically only take this power on known section. Do not forget that 4MW at 750V is over 5000A requiring massive cables. With these high currents there is considerable voltage drop resulting in the system often being rather inefficient. Even my local Tramway network (Manchester Metrolink) has had problems with voltage drop and recently had to put in some new substations at for example Brooklands because of voltage drop problems. In contrast high voltage AC systems can easily deliver train loads of 10MW or more, which is required for heavy freight or fast passenger trains

It's good that you finally mentioned third rail for trams, because i assumed you would have missed it completely. Also referred to as Ground-level Power Supply. I just want to add that many tram systems used to have third rails in the early days, as far back as the 1880's. They all had their issues and some were insanely unsafe. One in particular, Stud Contact System, suffered from a design flaw that make the electrical contacts that were flush to the ground to always be live. Meaning any unsuspecting thing passing over it and closing the circuit would be hit with significant juice. Another was a system that was always live, but buried into the ground with a "plow" that would make contact with the electrified rail. The principle was that since the live rail was buried, anyone passing over it would be safe. But of course it didn't work too well because random garbage would make its way into the slit and destroy the "plow" or get jammed between the contact point and rail. And anything that could conduct electricity, such as a strip of metal, could get in there and provide a protruding live feed that would make fireworks happen to anything touching it. And then there's the issue with snow, ice, and especially salty water which would electrify the surface... Third rail for street level trams/light rail simply doesn't make much sense.

Overhead wire for everything and supercapacitators for tram sections in historic city centers (like Caf technology in Sevilla and Zaragoza or Alstom in other places).

The M8's on Metro North are equipped to handle different power delivery systems and some of the old tram lines in Washington used below street power .

This is your most nerdy video yet. I love it

Thanks to you I've just realised why, in the first Mission Impossible film, they based it on the UK leg of the Eurostar route for an action scene: it has third rail instead of catenary. 😃 If only they had used a model of the TGV TMST instead of the TGV Atlantique.

8:32 DC actually has better efficiency at distance because there is a thing called skin effect with AC. "why then AC is used to transmit electricity at longer distance?". it is because AC voltage can be stepped up or down efficiently with simple Transformers. Higher Voltage transmit power much more efficiently than lower power, you can make ridiculously high voltage AC with minimal step up loss with just transformers. in this time because we have more mature semiconductor technology we can also make a very high DC voltage with minimal step up loss tho. that's why HVDC (high voltage dc) is very popular right now for intercontinental electricity transmission, the bonus part is we dont have to care about matching frequency like we do with AC.

I wonder if you will ever do PRT, especially Morgantown. Since you seems to be a lot more knowledgeable in public transit then many others.

Further to your mention of the lower profile in tunnels with 3rd. rail, where tunnel boring machines are used, in order to get the clearance for overhead catenary, there is a massive increase in the amount of ground spoil that has to be removed because the tunnel width is also increased, so to me, the use of 3rd. rail cuts construction costs considerably. Where existing lines are electrified, low bridges and tunnels do not need rebuilding., although here I would mention the South Wales Metro, currently under construction. I believe that the intention is for the tram-trains to use battery power in some locations, not only on the proposed street extension in Cardiff Bay, but also through the Caerphilly tunnel where the catenary will be grounded due to the low clearance and water ingress from the tunnel roof. The first Stadler tram-trains have arrived at the new Taffs Well Depot and are being line tested. I would be interested to see your take on the system in due course.

If there is enough room, overhead line is always the best choice. Rigid catenary is the best choice for tunnels, expecially for those ones that doesn't have enough space for catenary overhead and are long enough to don't have huge seasonal and/or daily termal excursion. Third rail should be relegate for tunnels without sufficient room to any type of overhead line, neither catenary nor rigid.

I’ve always thought overhead wires are really pretty

As someone from the South of the UK, I will say third-rail is nice for being visually unobtrusive, single and double tracks can blend into the countryside very easily.

The Rotterdam metro combines both. It is third rail in the city center and overhead wires on converted rail lines into the suburbs.

Decades ago, the Chicago 'L' (CTA/CRT) had far more mileage at ground level than it has now: (Douglas Park (Pink), Ravenswood (Brown), Skokie (Yellow) and Evanston (Purple) Evanston, Skokie, Lake Street (Green) used trolley wire power, while Ravenswood, Garfield (Blue), and Douglas used third rail. Furthermore the lng forgotten Chicago Aurora & Elgin Railway used third rail for most of its service to the Fox River Valley cities that it served, using trolley wire only in its Wheaton Yard, railroad interchanges, and the Fox River city terminals. Third rail is ALMOST universally 600 volts DC, although one Michigan interurban used 1200 volts DC. Also Bay Area Rapid Transit uses 1000 volt third rail. Most of the long forgotten interurban railroads used 600 volt DC trolley wire in spite of the rather long distances involved and the use of rotary converters to convert power from AC to DC (before rectifiers were technologically feasible). Thus the interurban from Chicago to Milwaukee required a substation every EIGHT miles to power their many heavyweight six car trains. Conversely the Indiana Railroad got by with substations every 15 miles as trains were short, lightweight, and less frequent. Light Rail Vehicles, old-fashioned streetcars and trolley buses universally use 600 volts DC power. But many other voltage and AC/DC arrangements can vary widely for suburban and intercity electrifications.

British Rail Class 395 Javelins like what you've shown in your video do still run at somewhat high speed (less than 230 km/h) but still have third rail capability

The New Haven Line from Metro North has both third rail and overhead wires.

At the end of 2022, Indian railways reached 83% electrification of its 68,000 kilometers of mainline railroad network. The US, on the other hand, only has 1% electrification. Nearly all US electrification is in the northeast corridor and the septa system. Somehow, Canada managed to be even worse than the US at electrification. Mainline electrification is virtually unheard of in Canada.

Great video, one type you didn't mention was overhead power from a pole as opposed to a pantograph. In San Francisco we have vintage street cars that run up market Street that use a single pole to take power and return power through the steel rails that the train runs on. There is a second wire which is used as a return for rubber wheel trolley buses running on the same right of way. It's an interesting case study of having two different vehicle types running using the same power. Not sure if there's any other systems in the world that share power between a steel wheel on steel rail street car and trolley buses on rubber tires, although I wouldn't be surprised if there's someplace in Europe that does that. Keep the great videos coming, thanks

And then (long ago) there was the Giant's Causeway Tramway in Northern Ireland, built as a third rail roadside tramway. Later mercifully converted to overhead.

The S Bahn Hamburg (Germany) uses 1200V DC third rail, but on the S3 extension to Stade the train switches to overhead wire power at Neugraben station.

Could you make a video where you take a look at the plans for the Tel Aviv mass transit system? Tel Aviv is a large metropolitan area that, while having excellent bus coverage, has not had a mass transit system until now. There's one now in planning and construction; the first line should be opened within a year, and it should all be complete by 2040. They have a full map of how it'll look at the end. There are three reasons I would like you to discuss it. Firstly, it's a mix of systems; three metro lines, three light rail lines, and a bus rapid transit line. I'm curious why they chose those different types for different routes, and you might have interesting insight as to the reasoning and wisdom of which method they chose for which route. Secondly, the vast majority of urbanism/transit content online focuses on either North America or Europe, with other areas of the world rarely getting a discussion. Thirdly, I've never seen any urbanism/transit content about my home country of Israel, and feel rather left out. I think this would make a really interesting video for the first two reasons mentioned, and I personally would like to see it for the third reason.

hey rm, please do a video about the belgian railway, i'd apprieciate it

Rigid Catenary also extensively use in new Underground tracks in Hong Kong's MTR network, Starting from West Island Line extension for Island Line when it launch service in 2015. The Latest, East Rail Line new track from Hung Hom to Admiralty is in full Rigid Catenary.

Another example of switching electrification as the service changes: Line B of the Rotterdam Metro: At its eastern end, it runs on a newly built light rail alignment, powered using overhead equipment due to a lot of level crossings. The light rail alignment allows for speeds of maximally around 70 kph. In its centre, it runs on third rail and largely underground, allowing speeds up to 80 k, assuming the vehicles can accelerate enough before the next stop. On the western side of the network, it follows a decommissioned heavy rail line where they hooked up light rail power to the old mainline catenary. Speeds climb to 100 k, thanks to wider stop spacing.

In Delhi metro, there is an overhead third rail supported by the cantilevers when the train runs underground ie in the tunnels

Newcastle’s light rail also uses a different method of electrification by having charging stations at the light rail stops

In the UK we have a really odd system where the south of the UK almost entirely uses 3rd rail and the north uses 25 kv overhead, and I mean mainline commuter trains, not just subways. Like so many London stations are electrical hazards cause they have both 3rd rail and overhead lol, some even have 3rd rail platforms, 4th rail for the tube and 25 kz for trains going north

Amtrak diesel locomotives run on 3rd rail when operating in Penn station to reduce enclosed space emissions

3rd rail is really cool in the UK!

if I ever encounter you (say, if you visit Crema in West Van), and it comes together that I receive the privilege of your company, I think I’d really enjoy sounding the mind of somebody possibly even more obsessive about great design than I am.

Reese, MBTA in Boston is looking at electrifying the commuter rail. They’ve recently said that they plan to roll out overhead catenary most places, but will be using batteries to bridge the gap where putting in catenary would be very difficult (under bridges, tunnels, etc.). What are your thoughts on a system like this? Are there any systems like this in the world? Do battery electric trains still have a lot of the benefits of traditional electric trains? I’d love if you could have a video on this, but a reply would be cool too

For the TTC subway, it is called the Traction Power. As the for light rail transit is called Overhead Contact System.

10:51 Russian and Post-Soviet depots use similar technology, the third rail is hanged up by 4 meters of the ground to avoid accidents for the workers

In Santiago Metro, new lines 3 and 6 use rigid catenary at 750VCC and National Railway (EFE) commuter, regional and national lines use 3KVCC double catenary just like in Italy

i saw in your video about double decker buses that you went to Richmond so thank you for that i hope you enjoyed it :) there is also little village (kind of) called Ham and also Petersham you could visit if you haven't already it is inbetween Richmond & KIngston P.s. and also if you want to know some history about it then i'm happy to tell you about it

Here in São Paulo we are using rigid catenary for the newer greenfield metro Lines (4, 5 and under construction 6 - probably). The older metro lines (1, 2 and 3) use 750 V DC third rail.

Can you please talk about the Prague transport system? I'm from Prague and even though the transport is incredible, it doesn't get any attention. Please make a video about it.

Hey! I enjoyed the previous version of this video and I'm happy to see a revamp of it! Do you have a video/could you please make one explaining different rail types and terminology? (eg. regional rail, commuter, light rail, etc)

I understand why the 1st REM line is overhead (it used an at grade overhead electrified line) but I would question why the 2nd REM line and Toronto Relief line is overhead, although snow might be the reason.

I am Italian and I live near Milan. Milan metro, as you said in the dedicated video is split up. The metro line 1 or the red line M1 uses DC third/fourth rail while green line M2 and yellow line M3 use overhead wires. I suppose M4 and M5 run on third rail since I never saw an overhead wire but it's difficult to see anything like that due to the platform screen doors. I found out that all the metro trains in operation are actually supplied with both third rail capting systems but also with a pantograph, making every equipment movable between lines. I saw it in person where a M2 train transited down at M1 station "Precotto" where a maintenance facility is located, supposedly for maintenance works. Our trains, especially the S lines use overhead wires but on the station of Pavia on the S13 line, for a slight moment the overhead wires stop and then come back at the station itself (terminus). I suppose there's a third rail under the train because it doesn't have any loss of power. Fun fact, during June this year, a thunderstorm broke down most of the overhead wires for trams and trolleybusses, pointing out how brittle things can be. Another example is from "Via dei Missaglia" where trams 3 and 15 run, a car hit a overhead wire tension pole and deviated the 2 lines for 3 weeks.

Another reason overhead wires alternate over the insert is that it ensures you maintain a good contact. And you technically could make a very short and thick insert and still have the same wear as a wide insert. It's not just the wear (shaving) that is an issue on overhead wires, it's that if you rub against the same surface constantly you will overheat the contact point due to heat from friction. This would anneal the insert making it brittle and also shave the overhead wire rather than the insert. Having it move back and forth along a wide area means the points not in contact are given time to cool down. Third rail shoes don't alternate over the third rail like overhead wires do. But this works ok because the third rail is wider with a bigger contact patch. They are also smoother than the twisted cables of overhead wires, so shaving is kept at a minimum. If you ran your hand at speed over a third rail (without power mind you) you wouldn't notice much friction or abrasion. If you did the same on a overhead wire (cable) it would be like running a file over your hand which would eventually cut your hand in two separate pieces from abrasion.

You should have mentioned the Conduit System used by the Washington, DC Streetcars. This is basically a third and fourth rail UNDERGROUND.

A hybrid system is the best option for long n wide distance rail track that crisscross various landscape .🧐🧐

Time for the Klang Valley intergrated transit system

Hey, loved the video, how do the costs of the two methods compare? I was always under the impression that third rail was cheaper to install, especially along pre existing lines. Or am I wrong?

Well Hong Kong is using over head wire but some of the MTR construction train are using electric power diesel engine or just fuel power diesel engine

The best solution I've seen for me are the Nice trams. Running on traditional overhead lines connected to buildings, but relying on a battery in places where catenary poles would have been disrupting to the historic sights.

Cough... Ties .....Cough ..... Great video!

I think we should havr looked towards the idea towards Thermoelectric- and Renewable power stations for railway electrification, I think that would sustain the envivorment and the efficency of Britians's railways !..

There are some tram systems in the classic era, like London, which used a third rail conduit despite running on street levem

An AC and DC system of the same voltage are equally lossy over distance It's just *much* easier to raise the voltage of an AC system to be very high, since you can use transformers for AC but not for DC

Thank you for this very easy to understand explanation of different electrification systems! In the context of electrification, could you tell us something about the legendary "crocodile" locomotive model you have on display in your background?

Is that a LEGO crocodile? Omg my man!

What about the underneath wire conduit that streetcars used to use