You'll find survivors waiting to be rescued throughout each stage now. You need to get near to them and the survivor will automatically come towards your locomotive. Be swift though because they can be killed by the zombie horde! Every survivor you rescue will increase the base damage of all your weapons by 1 point.
To help with making rescuing survivors easier I've now implemented being able to drive the locomotive in reverse. Press left CTRL to drive in reverse. Driving in reverse is at half speed and there is no crush damage against the zombies so do be cautious!
I think I've improved the explanation of what the controls are when you start a game. They disappear when you start moving.
I still have more work to do with respect to survivors. I was thinking that around the 90% mark there should be a place that you can stop at and your survivors will then erect an outpost. The fire power of the output will depend on the number of survivors rescued. This could be helpful for completing the 35 minute challenges on each stage. Anyhow I have more thinking and work to do there.
Good luck Choo Choo Engineers!