Correction, highest speed with lineside signals in europe is higher than 160km/h although in most countries its 160km/h. In UK it is 200km/h, in France it is 220km/h. On the French line thats 220 the first non green aspect a driver will see is actually a new speed limit sign, which is backlit, at 160km/h. I've always wondered if this is some sort of separate distant signal to extend the braking zone.
Also 200 in Spain (with ASFA protection system, at higher than 200 the ETCS system is required). About the pre-warning 160 sign you mention, we also have something similar in the form of a blinking green signal aspect. It's called "conditional clear", it means that the track is still clear ahead but you should reduce to 160 because you might find a warning yellow signal later. I think most countries allowing higher than 160 speeds with physical signalling systems have an equivalent indication to pre-warn fast trains
The "flashing green" was introduced at the SNCF: trains traveling at no more than 160 km/h could consider it the same as any "steady green"; instead the driver of a train traveling at more than 160 km/h had to slow down until the speed was reduced to no more than 160 km/h before passing the next panel. A pre-announcement signal (P) was also provided for mobile TIVs when presented. A similar pre-announcement signal was also foreseen for what concerns the TIVs of the construction sites (temporary signs placed to order the reduction of speed in correspondence with sections of line along which works are being carried out). Instead here in Italy, to allow circulation at speeds above 160 km/h along the "Direttissima" Rome - Florence, they invented the repetition of signals (Cab signals) with 9 codes, adding a second carrier to the one used for the "Automatic block with coded currents" of the American school.
Great video.. 👌 Maybe you could cover the topic of high speed trains, having in mind their popularity, controversy and neverending discussion of their feasibility.. but in more details because you mentioned it in previous videos... Tnx 👍
Uros, thanks for the comment. Certainly videos about HSR trains are in our plans. From the very idea of HSR, the technology that is applied as well as their influence on the further development of the railways. You can expect one such video soon.
The signalling goes inside the locomotives if speed higher 160 km/h e.g. Intercity Express (ICE) or Thaily. Same on Japanese monorail. Many Metro/Underground/U-Bahn use inside signal as security features too. Specially the typical fast train with 250/300/350 km/h travel speed can not see ground signalling so fast.
@@OldLordSpeedy In the US, cab signaling or speed regulation is more or less required above 79 miles per hour. Wayside signaling may be present, but such signals can simply say "just read the speed display in the cab."
Thanks for all the info. I would be interested what fall-back systems are in place, if there are power outages, the 4G network is unavailable, or any bigger computer sabotage happens. If there is no signaling installed on the line, does that mean that all freight and passenger transportation can be brought to a standstill on all those major transportation lines, just by knocking out those critical networks?
What a great explanation. I teach new train drivers this exact same subject (although in more depth) and your video provides a very good basic explanation that many people can use to start to understand the deeper signalling issues. If you don't mind I will direct my trainees toward your channel.
This is exactly one of the ideas of our channel. That people use our videos to educate young railway students and pupils. Please feel free to forward this to your trainees and feel free to play it in class as well.
I really love this channel. When I was a child 50 years ago I was a crazy railways fan. I loved my small electric toy trains and to assembling their plastic tracks. Growing up I got more interested on technical aspects of real trains, and you are teaching me a lot. Thanks.
So I'm a former signal electrician/ maintainer, and you absolutely nail the critical information that i find lacking in all other signalling content on RU-vid. Many people still think that signals operate because of Time intervals. "This signal is at Red, but after a time, it changes to yellow", etc. Thank you for getting the ground work 109% right!
Incorrect info. 100mph is not the speed at which lineside signals are no longer used as my local line runs 110 with 4 aspect light block signals and the max is 125 here using full signalling and signage.
Time Interval System. Until around the 1920s, here in Italy and in other European countries (France, Switzerland, etc.) the green flag or light meant slowdown, danger, etc. and the yellow flag or light did not exist. I would therefore kindly like to know whether the green, then yellow and finally red flag sequence seen at the beginning of the animation which deals with the "Time Interval System" is historically reliable or not. Thank you very much for your availability and collaboration
@@patrick_test123 for a joke, it was universal from Spain to Norway and from Portugal to Turkey. A vehicle from the UK could travel everywhere in Europe without needing an adaltor and vice versa if it fitted the UK's more restrictive loading gauge.
@@xymaryai8283 oh yea I’m sure because I did that watched that very signalling video during my training, plus the train depicted is the Waratah A Set which is in NSW painted in the Sydney Trains Livery
It's was a really nice sum up of the evolution of railway signalling. I did not even have an idea the Time interval Signalling existed. I suppose it would also be useful to mention that CBTC systems are currently only associated with metros and not yet with main lines. Also a few words on ETCS signalling
Thanks Harish for the comment. We agree with you. All this will be covered in future videos about signaling. We think that this video has hit the point and that it allows people who are not dealing with the railway to understand the basics of signaling.
@@RailwaysExplained My railway will be moving toward the CBTC system as part of stage two implementation of the ETCS ATP that you showed. I agree, another video on ETCS and CBTC would be good.
@@trainstrains1 I am pretty sure that the moving block system is part of ETCS level 3, which still hasn't been properly implemented on any railways. ETCS level 2 is "virtual block" it does not have line side signals, but it still has fixed blocks. This means that blocks can be made shorter more easily and trains can run for efficiently, but not quite as good as moving block.
@@pwhnckexstflajizdryvombqug9042 Hence why I said "moving toward". There is still a long way to go with implementing stage one on trains that are 20 to 30 years or more old before we can even look at going to level 2. However the plan is there for removal of the lineside signalling and eventually moving to level 3 which, as you correctly said, has not been implemented anywhere yet. It will come however.
Very nice video. Everything you need to know (in the beginning) about rail signalling, summed up in a simple and straightforward manner. Great analysis and conclusions. Keep going Railways Explained!
Actually, although 160kph (100mph) is a common limit for lineside signals, some countries, in particular the UK and France, allow running up to 200kph (125mph) under lineside signals. The UK also did do test running at 225kph (140mph) using an extra flashing green aspect, but this was never used in service (although the flashing greens are still present on the route where the tests took place). The main variation from the basic green-yellow-red system is speed based signalling. These tend to still follow broadly the same principal, but add in additional aspects (either multiple aspects together, flashing aspects or both) and sometimes will even display maximum speeds. Some systems will also have different forms of red signal, one being an absolute stop, and one being a "stop and proceed with caution". The UK has it's own variation on green-yellow-red which adds in an extra "double yellow" as an advanced warning, allowing trains to run closer together by reducing the block length whilst still maintaining the same braking distance.
I work for a train company, even though I'm not a train driver, I'm always on the trains, it's fascinating to find out the origins of the current signals in use.
You said that lineside signalling is used up to 160 km/h in Europe. This is not correct. The UK (which remains in Europe in spite of Brexit) has been running trains at up to 200 km/h for several decades. Richard Branson briefly had a plan to raise this limit a small amount, though it wasn't followed through. The only UK mainline route I can think of that only uses in-cab signalling is the Channel Tunnel Rail Link (300 km/h and 230 km/h for phases I and II, respectively).
Thanks for this informative video on railway signalling, From childhood i have been fascinated by the Railways and still that enthusiasm of train journey has not receded, i always take a train for a overnight journey, during my young age i used to see only Semaphore signalling and that too some had oil lamps at night, put up by the gangmen every evening and slowly this changed to lights with the cables from the signal switching post run to a distance with rollers The mechanical hand lowered or lifted up to show proceed was a marvellous and slowly colour light signalling takes over, i was waiting to hear you say about the keys transferred from one station to other y the loco pilot and this helps to operate the signal lever so that the loco pilot understands whether the block is clear or not clear. There used to be a bamboo bent like a tennis racquet and a leather wallet belted to this will hold the key, when passing a station the loco pilot drops his and grabs the one held by the gang men, this was lovely to watch especially during night when he holds the key with one hand and fire torch in the other, Please show more videos about signalling.
Hi, thanks for this and many other videos, @railwaysexplained ! If you could, Id love to see a video about ETCS and generally about radio-frequency based security on railways... thank you! :)
10:05 I am so thankful you showed good example as Korean. The blue train set is of Korail 371000 Series EMU operating on Gyeonggang line (means connecting between Gyeonggi and Gangwon province) Korail Metro. Most of Korean railfans think 371000s are special. It is because they can be operated on all 25,000V alternating section despite no control centers' approval. ATS, ATP, and ATC were installed in them as first subject of Korail all EMU series. (Of course they cannot be in Direct Current 1,500V ^^;;;) As locomotives, there are Korail's EMD GT26CW DL7573 ~DL7576 introduced in 1996(earlier than 20 years comparing with 371000s), which are worked as special engine on High Speed Rails; Relief Wrecking Drive TGV-K, KTX Sancheon, and EMU-260&320 of Korail. Unlike other GT26CW DLs in Korea, ATC(for TVM-430) were installed in the four. Thank you for reading and have a nice day sir. :)
Today marks a sad day for my country and the railway community. It is one year since a terrible and completely preventable railway accident happened in Greece claiming the life of 57 people. The most sad and outrageous part of this story is that our corrupt government is claiming the accident was caused entirely due to human error coming from a specific station master. This way they are attempting to cover up their gross neglect and incompetence and basically the fact that as of 2023 there was still a train network in an EU country that was operating on control principles from the 19th century This is beyond outrageous for all us citizens of Greece who know anything about how modern automation and control systems operate. It is an insult to our intelligence, and it is an insult to democracy in Greece and the EU. I have used your video to spread basic knowledge among Greeks and dispel the scandalous cover up by our government. I would really wish your videos you will start seeing a spike of views from Greece.
Here in the UK, the semaphore (mechanical) distant signal was a separate signal coloured yellow with a triangular notch cut out at the end to differentiate it from the normal signal It was an excellent video - I'm not sure the timed version of the signal was in place here in the UK but I could be wrong
The main difference with Distant signals is that they cannot show 🔴red. Modern ones show 🟡amber for _Caution_ or 🟢green for _Clear._ But yellow or amber haven't always been available... so WAY back when, it was red, green (for caution) and clear/white.
You mention in Europe that trackside signals are only used up to 100mph/160kph, but that's not quite complete: in the UK it's a little higher (125mph/200kph)
We can actually run up to 140 mph with our soon to be scrapped class 91 locomotives. The section of track where this is possible has flashing green aspects. The reason the trains do not run at that speed regularly is because of level crossing timing circuits and the viewing distance track workers need to be able to stand clear of the line.
In Britain the maximum speed is 200 km/h except for the high speed channel tunnel rail link. This speed was introduced with the diesel InterCity 125 in 1976. Britain is an exception to the rule that the maximum speed is 160 km/h if trackside signals need to be observed.
@Alfred Weber The requirement for a second man over 100mph was dropped I think in the early 90s, with the limit increased to 110mph. These days it is 125mph unless there is cab signalling.
it would be great if you could make a video explaining the cost of construction of various types of rails like high speed,Elevated,Underground etc I seriously dont understand y it costs soo much to lay 1 km of high speed rail
In the UK on permissive blocks (section of track) you can have more than one train provided the following trains can see the tail lamp of the preceding train if still in view. This occurs in freight only lines and at stations where multiple trains can share the same platform. Only on absolute blocks is the rule one train per block.
I believe the idea of permissive signals on automatick block sections is widespread. I'm a train driver between Spain and France and both countries have this system too. I would be surprised to find a country that doesn't.
@@osasunaitor thanks for that. I was sure that permissive block working might exist outside of. the UK as it is very useful but not being sure I only talked about what I was certain of.
In the United States it is very common for multiple trains to be in the same signal block. The following trains must drive on sight, though. The USA also makes extensive use of _permissive_ signals, which cannot show _Stop_ but allow trains to proceed on sight into occupied blocks.
It is a great overview of the evolution of railway signalling, thank you very much for this great content. Unfortunately, there's a substantial error in it concerning the colour coding of signals. In the beginning, railways used a different coulour coding than nowadays, where red also meant 'stop', but green meant the 'danger/caution', and white was used for indicating 'clear/proceed'. The current red-yellow-green scheme was first introduced in the UK in 1872. Railways in the US started using this new scheme first in 1905. Germany introduced the red-yellow-green system in 1912, other continental European countries switched to the new system in the interwar period.
Thank you for the informative video. Yes please a video on the newer signal technologies. Model railroader and electric railway museum volunteer here. Side note; an early version of cab signals was on the San Francisco Bay Bridge Railway. The worry was the bay fog would obscure line side signals. Operation was from 1939 to 1958. Abandonment was a crime.
This is an awesome video. Can you make one with the origin of railway travel, earliest locomotives and the like? The historical clips on the "Purpose and Elements of the Railway Track" were great, I'd love to see more of them.
The railway workshops museum near my house still have a few lines that still have the mechanical signals (although I’m not sure if they are still used or have been automated) One of the lines even has the switch point box although I think that may also have been disconnected. Edit: I only know this because the old line runs in between 2 of the main buildings at the shopping centre near my place. Look up rRverlink, Ipswich QLD and you’ll see it
SECTIONS are NOT BLOCKS. The system using "stop watches" is actually TIME INTERVAL BLOCK. Meaning that when a train leaves Station A, the signalman exhibits a red flag for eight minutes. From 8 to 15 minutes after the train left station A he exhibits a yellow flag, & after 15 minutes has elapsed he exhibits a Green flag. A pointless programme if you don't know what you're talking about !!! ❌
Thank you Durga. You can expect a lot of interesting videos in next period. We are planning to cover all aspects of rail system. Did you manage to watch our previous videos?
The "flashing green" was introduced at the SNCF: trains traveling at no more than 160 km/h could consider it the same as any "steady green"; instead the driver of a train traveling at more than 160 km/h had to slow down until the speed was reduced to no more than 160 km/h before passing the next panel. A pre-announcement signal (P) was also provided for mobile TIVs when presented. A similar pre-announcement signal was also foreseen for what concerns the TIVs of the construction sites (temporary signs placed to order the reduction of speed in correspondence with sections of line along which works are being carried out). Instead here in Italy, to allow circulation at speeds above 160 km/h along the "Direttissima" Rome - Florence, they invented the repetition of signals (Cab signals) with 9 codes, adding a second carrier to the one used for the "Automatic block with coded currents" of the American school.
BRITISH "PERMISSIVE BLOCK WORKING" - MULTIPLE TRAINS IN A BLOCK !!!!! This programme begins with Quote "Only one train can be present in one segment of line at one time" Unquote. NOT if you have "PERMISSIVE BLOCK WORKING" which allowed trains to follow each other on condition they did not exceed 25mph, and stopped at least 200yds short of the train ahead. (And could IGNORE the semaphore signalling provided) Indeed on such lines many of the trains were "unfitted" (NO train brakes except the loco & Guards van) ! This system was of course confined to freight only operation. But could be seen in use on the 4 track Midland Main line during "off peak" hours on what were nominally the Up & Down Local tracks. It was finally abolished by 1972.
A correction is needed here... It is not true that trains travelling faster than 160 km/h always use cab signals. I can give you the example of the (non tgv) line Paris Bordeaux, where some long sections allow up to 220 km/h, only with lateral signals. There is even a signal aspect- flashing green - displayed before yellow, to instruct drivers to slow down to 160 km/h. There are similar situations in Italy, Germany, and UK.
Dear Marc. Thanks for this information. But we need to say that cab-signalling system is mandatory in most of the countries where trains are allowed to exceed speeds of 160 km/h. Reason for that is because it is difficult for train drivers to see signals at higher speeds. As you mentioned there are specific cases. In these cases a so called multi-aspect signalling is being implemented. This solution requires that if operating speed of a train is 200 km/h, train driver needs to see a "slow to 160" signal in the first block, and then a stop signal in the 2nd block if there is a need. In addition, this solution does not solve the other problems with high-speed operation, the difficulty of seeing signals at higher speed, especially in marginal conditions such as rain, snow, and fog. Cab signalling solves these problems. Bringing the signals inside the cab makes it easy for the train driver to see them which is great contribution to the safety level of railway operation. Regards.
The flashing green aspect on the East Coast Main Line was basically a fifth aspect with the sequence to red as follows; Flashing Green, Green, Double Yellow, Yellow then Red. The flashing green permitted speeds up to 140mph or 225kph (which is why the British Rail Class 91 loco, Mk IV stock and DVT consist was originally marketed as InterCity 225. The Mk IV rolling stock profile was designed to allow the train to tilt at the higher speeds.) Running on ordinary green aspects gave a MAXIMUM permissible speed of 125mph, dependant of course on the permissible speed shown in the Sectional Appendix and by the lineside signs.
@@PhilSmith71 worth pointing out that the 5th aspect allowed 140mph without having to reposition the signals. 4 aspect would be fine for 140mph, of the signals were respaced, which would have been a painful project. Also, worth pointing out that 140mph was allowed if there were two drivers, to orovide redundency. It was only single driver operation that limited speed to 125mph. A number of years later the safety director changed it so that 125mph was the limit for lineside signals regardless of jow many drivers.
@@FabianEason I did know that the Flashing Green was the existing Green aspect except that it flashed, but thanks for clarifying that point. ☺️Interesting to know about the other facts though!
Can the overspeed-detection capability included in ATP be programmed to detect if an overspeeding train isn't slowing down and send ahead a warning of a potential runaway?
@@blue9multimediagroup I was more thinking situations like a brake failure, overloaded train running downhill, etc., where the problem is the brakes' ability (or lack thereof) to stop the train, rather than the application (or lack thereof) of the brakes.
There was one other system for use on branch lines. A token was used to allow a train to operate on the branch and it was returned when the train left the branch. Of course, this limited the branch to only a single train at a time.
