Don, I would pull down the volume of the train whistle in the middle section a bit. One other thing you could do on the fade out at the end would be to put huge hall reverb onto an aux bus, while you are fading out the song, gradual dial in the reverb on the aux buss. Along with that fade IN of the aux bus, gradually dial out some high frequencies using EQ. This will simulate that train moving out of the scene even more.

-Scott