passenger train safety (in the US and elsewhere)

[coremelt]

@Noel_Prosequi

Coremelt, if the bullet train rails are continuously welded with no gaps, how do they avoid thermal expansion and contraction issues? I can think of ways of arranging places where rails slide past each other in some configuration designed to allow for expansion, but these ideas don’t fit well with the continuous welding you describe.

It’s not just the bullet trains, Continuous Welded Rail is pretty common in many places. How do they deal with thermal expansion? I’m not an expert but as far as I know they use a combination of absolutely rock solidly fastening down the rail so it cannot expand or contact and then they also pre-stress the rails while expanded or contracted. I agree it seems like black magic but I can assure you it is real. They do occasionally have to use expansion joints in special cases but not very often, maybe only once every 30 km or so.

Railway track

I can testify personally to the end result, even while on the highest speed sections of the Shinkansen (roughly the section near Mt Fuji), there is zero vibration or bumps from rail sections. It is so unbelievably smooth that it kind of messes with your head to feel no sensation of moving and then look out the window and see the landscape flying past at 250+ kph.

[Me_Billy]

If the driver of the train was texting on his cell phone, might be a good idea to not go by train at all! (Or drive on a two lane road, walk across the street - Probably best to stay home!)

[Corry_El]

@Noel_Prosequi

Coremelt, if the bullet train rails are continuously welded with no gaps, how do they avoid thermal expansion and contraction issues? I can think of ways of arranging places where rails slide past each other in some configuration designed to allow for expansion, but these ideas don’t fit well with the continuous welding you describe.

‘Continously welded’ track, which is also common in the US, is not literally continuous. The segments of rail are just a few miles long rather than 10’s of feet long. Thermal expansion is dealt with by expansion joints and by pretensioning the rails, since it’s easier to hold the rails in place under tension than compression.

A different point I’d make about train safety using NJ Transit as example is passenger v non-passenger. The woman killed in the accident this week in Hoboken NJ was not a passenger. NJT may still never have had a train passenger fatality since it was established. However deaths of non-passengers are not rare, a high school classmate of mine died that way (not clear if suicide). And the fatalities per billion passenger-km in reference link above must be limited to passengers if only 159 deaths in the whole US over the 20 yrs up to around 2011. NJT and Amtrak killed around 400 non-passengers in that period in NJ alone, and hardly any were from trains crashing through barriers like this week’s tragedy. Rather, pedestrians or motorists were able to get to places where a normally operating train hit them.

A fatal trend: N.J. train deaths have increased since state launched safety...

[coremelt]

@Corry_El

‘Continously welded’ track, which is also common in the US, is not literally continuous. The segments of rail are just a few miles long rather than 10’s of feet long.

Ok perhaps it’s because of the speed they get to, but the perception from a passenger’s point of view is no gaps at all, literally you don’t feel any segment joins on a Shinkansen when it’s at speed. I know there must be but they are imperceptible.