I've seen ICE cab ride videos where the driver cuts back power before entering a tunnel. Does anyone know the reason for this?
jack#9468 Okay that might make sense. So you don’t know of any practice that involves cutting power just because of the tunnel? My thought was it could have something to do with the air pressure caused by entering the tunnel at speed.
Never heard of cutting power to go through tunnels, unless like you've said, it's something to do with the air pressure.
How effective would that be though? Cutting power, losing a couple km/hs, won’t do much for air pressure would it? The train would still be going at a great speed surely. My theory would be perhaps the tunnel is on a downhill grade which, to me, would justify cutting power.
It makes no difference in driving experience! It make more sense when you leaving the tunnel if you reach a wet track part after a dry part... I think he was early or its a small tick of the driver. I can not imagine it will change or improve someting at all. Neutral sections are not in tunnels at all in Germany
The simplest answer would be an oncoming speed limit. Driver usually cuts power, smoothly applies brakes, at target speed adjusts AFB (if PZB supervised, under LZB AFB must be set to MAX), then reapplies power.
If I’m not mistaken, tunnels entrances are shaped in a particular aerodynamical shape, to allow trains to go in on certain speeds, because of the obvious difference of pressure. Of course for passengers comfort, the train has to be perfectly sealed. Maybe the driver slow down for a speed reduction as Spike said. Can anyone confirm that neutral section are dealt automatically on high speed lines ?
First with turnback the throttle the train is not really slowing down or you do it kilometers before the tunnel and not in front, as i written already there are no Neutral Sections in tunnels in Germany. And in 99% so far i know they have no sections on Hispeedlines either.
I asked if neutral sections are dealt automatically on high speed lines in general, not inside tunnels specifically.
Any engineer placing a neutral section / Schutzstrecke inside a tunnel is playing with the lives of passengers.... Here's a nice tunnel boom video
Why? A neutral section has no power in it right? I guess its more easier to maintain this part of OHE outside a tunnel
Why? Imagine your train being stopped in a tunnel (forget Nbü for a moment) exactly with the panto in the dead zone? A fire? Panic. No escape. Where's my EuroDual?
For the record you never stop as a train driver in a tunnel. This is in German called a "Betriebsgefahr" totally prohibited.
Most modern ICEs have the system that detecting tunnels automatically "tunnelfahrt" and turns off manual emergency system and instead of stopping the train the traindriver get an alarm and the traindriver chose where he can stop
That's why I mentioned "forget Nbü" which is activated in case a passenger pulls the emergency, so the train is not stopped inside a tunnel. When designing railway infrastructure, you must take all possible risks into account, a failure of any kind. That's why there must not be a neutral zone inside a tunnel to prevent exactly this. This should answer your previous question why there's no neutral zones inside a tunnel.
This is the video. Not sure if it will properly embed. It's not every tunnel (the ones where he's at idle obviously don't count) so maybe I'm reading into it. I did drop a question on the video so maybe we can get a definitive answer.
TSW has signals inside tunnels, so I assume they're there IRL too, and if they show a stop indication the driver must stop. But I can quite see that coming to a halt inside a tunnel would be strongly deprecated.
Hehehe yeah if that was the case... We talking here about a track where you drive 250+ and you never seen signals on time so there is LZB\ETCS to see whats come!
So are you claiming the signalling system means there can never be a stop signal inside a tunnel (whether inside or outside the cab)?
No thats not what i mean... The driver get the signaling in cab at 160+ speeds.... In Western Europe, Germany we have a system that shows you upcoming speeds and signals in cab. LZB or ETCS
From the video creator: "I reduce the power before the tunnels, as the track condition outside is different than in the tunnel due to the rain. If the wheels suddenly have better grip in the tunnel, the whole train jolts" I guess it has to do with drier rails inside the tunnel. Very interesting
Do you have any sources for this? It sounds rather implausible when most countries have stop signals in tunnels. If you're taking all possible risks into account, one of the most obvious is that it's impossible to guarantee that a train won't get stuck in a tunnel... Except they were quite clearly talking about lines that do not have cab signalling.
Why are you starting fights everywhere here? I have said that for the event of a train coming to a stop in a tunnel, electricity to get away must be provided throughout the tunnel, therefore no neutral sections. Please read the whole discussion before starting arguments (which you apparently like to do.) I've put you on Ignore, because all your latest posts are highly quarrelsome and this was a nice respectful discussion so far.
Sorry i find as already written your'e behaviour al little frustrating.... I will not answer anymore on you're question... If you need awnsers check the world wide web!
Thats not what the question was, or i may wrong he asked before entering the tunnel.... So what i already written earlier that make more sense if you leaving a tunnel and you get on wet tracks... So or we do not understand his question or this is not the correct awnser..
