Okay. A couple of questions/points:
Firstly, just for clarification (I don't know if it actually affects anything, but pays to know), which game is this supposed to be for? Half-Life, HL Deathmatch, Counter-Strike, etc.?
Secondly, what is the loop supposed to do? Maybe you cut it out of the file you uploaded, but retriggering those trains doesn't do anything.
Thirdly, I changed nothing but putting some func_walls in (that have toggled textures) with the same names as the trains, and compiling that shows those multi_managers looping just fine. (Testing in Half-Life.)
Y'know, just to rule out some difference in our editor/compile setups, maybe just test this out (and then compile yourself) to confirm. https://www.dropbox.com/s/sfqyxl7ubrjklt0/testmapx.zip?dl=0
I apologize if I'm not reading the issue correctly, just trying to establish exactly what it is we're trying to do