In the save file when I place a cargo wagon behind the two locomotives in the station the game crashes.
log file:
https://www.dropbox.com/s/bmcc1zc5j8288hc/factorio-current.log?dl=0
Save file:
https://www.dropbox.com/s/7i430meupm9vxgw/placecargowagongamecrash.zip?dl=0

This is a map from 0.12 ...