CFD Online Discussion Forums - Help need in modelling train-tunnel interaction

hi, i'm trying to adopt sliding mesh and dynamic mesh approach in studying the effect of train entering tunnel.

the usual approach is making tunnel move while train stationary, but i wish to do the opposite. i can't get my sliding mesh to work.i've trial and error alot of different configurations already but still problematic i have a few questions.

1)is my approachs of using sliding and dynamic mesh and making train move correct in the first place

2) to use sliding mesh must my train block be touching my ground surface or can the train block be lifted off slightly, i dunno y but i kept getting either "segmentation violation error", or "grid interface not a pair"

3) i oso tried a configuration of putting my train outide a air volume block and set the train to a velocity, but it doest move...

4)my problem is an unsteady compressible flow problem, so i wish to use coupled implicit with ideal gas and pressure inlet/outlet which shd be well posed BC according to the manual though many ppl uses velocity inlet/pressure outlet. i'm using k-omega for viscousity. i used all these options but i always get my max/min temp and turbulence limits exceeded

5)for dynamic mesh, issit the i have to write a C file defining the motion of my train?

is there any one out there who can give me some advice??