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miguel.berrozpe November 5, 1998 09:41

HELP! rail tunnel pressure problem
In a hypothetical refurbishment project object of an MSc dissertation in rail systems engineering (Univ. of Sheffield), I am considering the feasibility of laying and clipping cables inside a continuous metallic tray that hangs from the ceiling of an underground tunnel for rail mass transit. The tray itself is about 30 cm wide, and hangs about another 30 cm apart above the train roof (obviously, this has no overhead line and therefore no pantograph). The train's maximum speed would be 80 km/h (although the whole design should be valid for future 100 km/h), and the tunnel itself is of relatively small profile i.e. exceeding the train's dynamic envelope by about 50 to 60 cm in each direction. At stations, there obviously an enlargement of the tunnel.

In the design of the cable tray device, I am confronted with different systemwide aspects, such as vibrations, earthing, installation, maintenance, etc. A critical issue is obviously the "shockwave" applied on the tray by differential air pressure in the tunnel as the train moves. Unfortunately, I have no idea of CFD (I am myself electrical engineer), so that I pose here the following basic questions:

- Can somebody tell me what would be the typical differential pressure on such a tray surface, when a train rushes below it, with the numeric values mentioned above?

- Would there be an extra pressure effect if the tunnel is wider but allows two trains to rush in opposite directions, creating a pressure peak when they cross each other?

- Are special precautions (e.g. reinforcement) needed at the entrance and exit points of the stations?

- In general: is there some good online documentation for beginners, for such a problem statement?

As I otherwise never visit this forum, please reply also at my e-mail,

Thanks for your support !!!

sheikh nasir February 14, 2012 09:35

train moving in tunnel help
i am working on train moving in tunnel. i am getting floating error:invalid number. can any one help me. my email is
plz help me


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