Why Do Leaves Cause Train Delays? | Bang Goes The Theory | Earth Science 

Hang them by the neck

Defund leaves

Or just have RHTT season

Only logical answer right here folks

Trees are shaking being frightend

+j0584924 It's a tv series. Not an internet series. These are but short clips.

+j0584924 then watch vsauce

+Sandwich247 Now that makes sense...

+silvk1000 I love Vsauce. It's a bit different from this. He builds up the ideas giving food for thought after the end of the video. It somehow makes sense. Michael almost always ends up with "And as always, thanks for watching". Here it's like they cut up the video, not only the idea.

i think this is a UK pheromone with the leaves causing train delays, we only get delays in america with heavy snow or down trees and when people jump in front of the train/rail.

Sebastian Rosenberg tgv12. Stopped by a shunter

@@thegreypenguin5097 meanwhile on the Caravan Train: *on fire*

SPEEF AND POWER!

Good to see they’ve upped the line speed on Merseyrail from 60mph. Always felt there were parts of the network that could handle 70mph, certainly the 507/8’s could.

+Ze Rubenator Have fun in prison.

+Aminus Vox It's not technically illegal.

+Jake Long I think in most cases the law would find it vandalism of govenment property -- er, train property -- it's illegal to just hang out on the tracks regardless, at least here in Canada.

aqouby It's not vandalism, it's washing.

+Ze Rubenator OK tell that to the police when they confront you.

James Eaton I have never seen a subway use sand since it would short out the electric connections. Diesel powered Commuter and regional trains do but they are much heavier and need all the tractive effort to get started.

Hi Charles, I've never seen a subway train with a separate locomotive. The electrical conductivity question is, in practical terms, not a problem - Amtrak's high speed Acela trains still haven't sanders. As the sand is only applied as required, and only one of the 16+ locomotive wheels has to be making good contact for the electrical system to work, the sand is more traction help than electrical hindrance.

Train driver (locomotive engineer) here - we do have sanders, and they do provide grip, but it is never _that_ good, oh, and icy tracks aren't slippery due to the immense pressure under the wheels. To give you an idea we recently had one of our modern electrics slide roughly 300 yards to a stand, it is fitted with sanders, WSP (think abs) and disc brakes that are like 4ft across on every wheel (32), it was going 12mph and still took 300 yards to stop. I was driving before sanders were standard (mostly a cost cutting reason) and have known a 1/2 mile slide on a tread brake train at just 33mph.

In Germany every powered rail vehicle and cab cars are required to be equipped with sanders by law since ages. Fist because it is considered way to unsafe to operate a train without at least one sander, that could slide along like forever on downhill tracks. And second, because the safety system needs a speed and distance signal to work, that is taken from a sensor on a wheel. So sanders were primary intended to maintain safe stopping distances. But of course are used to get more traction too.

@@denzzlinga Same here in Sweden, all trains have sanders if the train encounter slipperyness

@DremoraValkynaz ... I don't know what point you're making.

+kd1s true.Sometimes the squeal of those squared bearings is enough to make you wanna jump out

+revmpandora And lets not talk abotut the single deck 500 series commuter rail cars. The Amtrak guys all say the wheels on those are square.

+kd1s I wasn't aware of that one. You've given me something to do for a bit now; thanks!

😲😲😲 good grief! & I thought NJT comets over here were shitty!

+MrCube17 Actually I think they do, however its just installed betnween the wheels and the chassis. Normal friction based brakes aren't just powerfull and durable enough. I know yuo ment this between the track and the train but I just felt like mentioning it.

+puskajussi37 you are wrong. the german ICE3 has magnetic breaks. they are lowered to a couple of millimeters above the track and break the train by eddy currents in the track. but that heats up the track quite a lot so they only do that on specially prepared or tested lines. the old and outdated infrastructure in britain couldn't handle the thermic expansion of the track under electromagnetic breaking.

+MrCube17 Hornby did this on some of their model trains

+puskajussi37 I did mean between the track and train but that's pretty interesting still

+swunt10 Are you sure they use induced currents ? Because I know some looks like they are but in reality they are half-magnetic. They use electromagnetism but mainly to push (pull?) brake pads onto the tracks.

+Enzo Cavalli Nope, doesn't work for freight at all for example, which would mean having to build a system for passengers and one for freight. Aside from that Maglev is an even more delicate system than the old railways, they work perfectly in a perfectly organized world, but let a natural catastrophe or even an conventional war come and they are unsuable. Remember Railways ran during the worst of the blitz and until the last day of the war in germany, even when nearly everything around them was reduced to rubble. There is a lot to say for that kind of ruggedness. BTW. we don't even need a war, could you imagine running a maglev in conditions like on the Dawlish sea Wall, with the constant saltwater spray?

+LupusAries Inductrack can carry freight on a level comparable with traditional trains (actually, it's better in both weight ratio of wagon:load and power required) and is simple similarly to railways, including that the track is completely passive and it can generate lift without power. The main and practically only disadvantage of maglevs is that you need to build completely new and separate infrastructure and the initial price is therefore extremely high. (A similar issue is that standard track gauge is quite small for so much freight transport needed by the current world but any change is very unlikely because it would break compatibility with current infrastructure.) Permanent magnets are similarly susceptable to corrosion from saltwater as railway tracks but compared to railway tracks, they can be easily coated without trains scratching the coating off. Train tracks are quite delicate as well, and they took a lot of resources to keep operational during the war. Difference in the gauge may cause the train to derail at a switch if the gauge is just 10mm wider (for standard gauge), or damage/destroy the track if it is 15mm narrower.

Jan Sten Adámek Interesting, do you have an sources concerning the Inductrack? I would like to know more about it. As for normal gauge being rather small, well the issue there is mainly the loading gauge, Britain has a few very restrictive gauges, where you can't load much, the European loading gauge is wider, but the US gauge leaves even more space than that. By current infrastructure you mean not just the Bridges but also the alignment of the tracks, i.e. the line itself? As with a broader gauge you have to have a wider curve radius for a the same speed, although generally the wider the gauge the higher the maximum speed. (If we're discounting drag, especially frontal area drag.) As for wartime service using up a lot od resources, agreed, it did. Service was also not maintained on the pre-war levels, but it kept working, even in the most heavily bombed cities. Ok, could you elaborate on the tracks being rather delicate? Aside from the problems of it being out of gauge, which is a known problem.

LupusAries en.wikipedia.org/wiki/Inductrack Wider gauge has larger carriages which means greater freight capacity, something train networks in Europe would desperately need. You can search for Brunel's gauge or Breitspurbahn (as an extreme example) to learn more about its advantages. Maglev trains are much wider than railway trains for that reason since they don't need to be compatible with any existing tracks. Broad gauge does require straighter curves for the same speed, however the much more problematic part would be that all bridges, tunnels and stations would need to be expanded to accomodate it (which is one of the reasons why Brunel lost, switching to narrower gauge is just much easier). Being out of gauge is the main problem, however there are quite a lot of factors which can cause it. Modern balastless track slabs solve a lot of those but maglev tracks have the same advantages because they are inherently slabs as well. Inductrack tracks are moreover just an array of strong magnets and loops of (unpowered) wire which can be prefabricated and transported to the construction site very similarly to railway tracks. For the seawater sprays, railway tracks suffer from corrosion (rust). Something that maglev tracks don't so much because they don't have any exposed steel.

Why bother? Rolling resistance represents a miniscule portion of friction, especially as speeds increase. Air resistance force scales at the square of velocity; friction with rails scales linearly. High-speed transport would do a lot better to worry about wind resistance, either by making trains more streamlined, or by using airplanes, which operate up where the air is naturally thin.;-)

+danwic than a single leaf, there are a lot of leaves in autumn as you propably know.

+DiplomatDread I just saw the video again - I thought they had applied it to several places, but they only applied it to one area. problem solved.

+danwic It's not a leaf that's the concern. It's the accumulation of crushed leaves mixed with water. So the tracks have a thin layer of what is essentially powdered leaves, and when they get wet, the tracks are coated in a very thin, slippery substance, more slippery than soap. See 1:45 to 2:00 in the video.

danwic - it gets drawn along the rails, if you go to a station surrounded by trees you'll probably see it - like a black coating on the rails.

Yes.

+Luis Mendez Not just Britain!Every country with leaves and rain..

+Computer Addic Don't think so. Snow, rain, Ice... no problem in Austria

Leaves will be a problem for all railways. As a train driver, I assure you that leaves are much more of a problem for us than snow or ice. The worst conditions for a slippery track are lots of leaves (usually right after a storm) - that can cause problems for several days - or the first couple of minutes of light rain when it's been nice and dry for a while, but that only lasts until everything gets properly wet and the greasiness on the rails goes away. Snow and ice rarely causes slippery rails. The problem with snow and ice is usually related to other things around the rails, most commonly (at least where I work) it's the snow that gets compacted in the railroad switches, causing them to get jammed. Now all our railroad switches are normally heated to prevent this, but like all things exposed to the weather all year round, these things can occasionally break. Considering the amount of switches around any normal railroad line, this will inevitably happen from time to time.

Orku5 well that isn’t leaves is it. You can treat ice with anti ice but you can’t treat LEAVES!

well it kinda does.. trains have to accelerate slower and break earlier when running on lines known for low adhesion issues, that causes delays.

Al Paca it right, plus not to mention that most of Britain's rolling stock doesn't have sanding gear fitted

Al Paca Timetables are produced many months in advance, the reality is most of the worst of the low adhesion occurs for only a couple of weeks (red days), with only one or two days being particularly bad (black days). Weather plays a huge role in determining what weeks they will be (the forecasts are issued on a day-to-day basis, and vary around the country) unless you want 3 months of timetables running a significantly less frequent and slower service just in case then you have to just accept delays for a few weeks. As an example on a metro service of 30 minute typical journey times it can easily add 5-10 minutes to a journey on the worst days, this would result in a 33% capacity reduction on the timetables. That is without damage cause by wheel slip, signalling issues or other problems it can cause.

Wheel slip problems can also occur on the most odd occasions and then you are stuck with delays no matter what you do. Pollen in combination with light rain, frost, condensation caused by shifting temperatures, grass, an oil drip from a vehicle, nearby industry exhausts and so on... The easiest way to create high precision schedules that cover most of the year is to always have the trains running at about 75% of the lines top speed. That way it gives the trains a fair chance of catching up whenever delays occur. Unfortunately it annoys people to wait at a red light because the train is in effect early and most lines don't always have the capacity to extend a minor margin. Therefore the schedules are mostly run on a very slim margin and trains often risk delays.

It's easier to blame people than nature. Nature is never at fault. Leaves and ice also affect electric rail lines. If you've ever seen sparks fly on the rail or overhead wire its because of contact issues. If you've ever driven in a big city you'll see huge delays on interstates after a rain. Oil deposits on the road for days when it's not raining and the concrete just soaks it up, but add a little water and it's like skating on ice. Car wrecks everywhere lead to slow downs.

+Sinky I think the brushes would be eroded away before the train gets to the end of the line.

Or sanding equipment...like they used to lol

Sinky because it is more or less a liquid on the track

nikki, they have sanders - while it definitely helps, it isn't the ultimate solution many think - we recently had a low adhesion related incident where the train was doing 12mph (with sanders and the brake in emergency) and it took roughly 300 yards to come to a stand.

@Geo Thomas Because he doesn't understand physics.

Ahh,good pun

MarcAFK they already use this, it doesn't help much

ironmatic 1 Welcome to the internet, my friend.

agreed, but I am a real expert.

Snow and ice can become packed into the flangeways of switches and level crossings, becoming solid enough to lift wheels passing through them, in some cases completely off the rails.

Then I wonder how the Ottawa rapid transit system will do as it is going to be mostly not covered. I suspect that it will not be able to run some days when we get ice storms. Probably they will have to get jet engines mounted on a small heavy wheeled/tracked vehicle to unthaw things. That is what the two big railroads use.

+oldfartatplay1320 Major bummer, man. I hope you're back to normal now.

+deezynar Thank you! Very kind of you. That happened back in the late '70's. I've never been able to pitch a ball properly since. But life goes on, life goes on...

I hear what you're saying. My body is twisted a bit from an accident I was in. You just carry on the best you can.

Leighton Buzzard NGR

+retepaskab That is exactly what happens. Usually mid-Oct to mid-Nov.

That don't always work in every system so you can't say that.

Is that just soap? Or do British people call something else "Washing-up liquid"?

+Dogeasaurus Rex yes it's just soap but in the UK it's a certain soap we use to wash the pots and pans strange I know

Kevin Pickard So dish soap?

+Dogeasaurus Rex yes basically main brand we use is fairy washing up liquid

+Kevin Pickard the more you know... ☺

Not as simple as you think

The brush would need replacing a lot

This is from the "Bang goes the theory" show last year (for the BBC)

Razor2048 it's not that simple, it's a squashed greasy residue, not actual leaves. You need ultra high pressure water jets and thousands of gallons of water to remove it effectively at any reasonable speed.

it would wear out quickly and not be effective on leaf residue.

water jetting equipment is huge and only works up to 60mph

I'm calling the cops

Thanks for the delays

I'll admit I've put a a penny or two on a track, and then, after a train had passed, went and retrieved the resulting copper wafer.

Yes but too stupid to think of doing that!

How would you even go about doing that?

Shooting air ifront of the tiers?

***** Except that wouldnt work. The leaves are not dry, they are wet which requires alot more air. If you combined that with the train going 160 km/h you need some fans in front of the train.

Oh my... You think i was talking about air from fans? Wow.. No, i was talking about high air pressure, and the train got alot of just that, or get a rotating brush as they use when cleaning the roads? Or combine them.. It cant be that hard to solve this if they wanted to..

technically it causes lumps on the wheels but people don't understand that - especially when they are referred to as 'flats'

Thats what its called in Australia also.

Two peoples, separated by a common language.

London Biker GoPro that will cause delays because then they need to close that line to clean it

CapsRockTheRed don't see why they need to close It, it's just another train running on the line. In some countries i have seen maintenance trains run in between normal trains that grind the rails for instance, surely you could just as well clean the rails with another special train as it moves along.

we've already got the equipment for it & here's one of them ukrailways1970tilltoday.me.uk/Norwich_DRS_rail_treatment_train.html

They do exist. We use them every autumn on our railroads here in Denmark. I'm sure most other reasonably well-maintained railroads have them as well.

Leaves is the plural of leaf.

+dc2008242 I'm sure if it was that simple , someone would have done it.

extrude22 idk, I seen another comment afterward where someone was saying that some of them have blowers

+dc2008242 none of the passenger trains in the UK have leaf blowers, neither do freight as leaf blowers don't solve anything as the leafs will just be sucked back onto the track by the next train.

***** but that wouldn't matter if they all had leaf blowers

dc2008242 the leafs would be sucked back onto the track by the trains own carriages aswell so they'd still get crushed, some of our trains have 10 carriages so it'd be ineffective.

+Anton Morris They use sand...

Liam Taylor-Warren Well said, disc brakes have indeed exacerbated the problems. The old 'slam-door' trains built in the 50s & 60s had 'clasp' or tread brakes, as you say, the cast iron brake block was applied directly to the wheel tread or tyre and very effectively 'scrubbed' the tyre of leaf mulch. Whilst stopping distances were still increased during leaf fall season, it was no where near as bad as today. Sadly, most trains with tread brakes were withdrawn and scrapped from 2005. So, we're stuck with the disc brake. And as for peoples suggestion of a brush or something in front of the wheel, you would be surprised exactly how 'sticky' that leaf mulch is. Once its crushed on to the rail, it really is exceptionally difficult to remove. There is a water jetting train that runs a continuous (ish) circuit, but, particularly here in the southeast, there is a lot of routes, most with double track, some with 4, 6 or even more tracks, its a huge job to water jet and sandite so many route miles. Frankly, I don't think people realise that.

And another reason not to take Amtrak.