It seems most of the concern here is about battery charge time. With the lipo batteries that most here are using these batteries will charge in less than thirty minutes with a proper lipo charger. I'm an RC veteran with over thirty giant scale airplanes and half my planes are battery powered. With that said it pains me that there's been no mention of battery safety here.
Lipos are time bombs if you drop one on the floor or something happens to your charger or cell balancer.
I would never leave a lipo in a train unattended. My lipos stay locked in a steel 50 Cal ammo box and the ammo box stays inside an old wood heater with fire brick. Also I never charge my lipos unattended. I always have them in my sight when charging them. when they're charged I either put them in a plane and fly or they go back in the steel box.
The reason I keep the ammo box in an old cast wood heater is because one three cell lipo can blow a steel 50 Cal ammo can apart and shoot five foot flames like a blow torch. Don't ask me how I know this.
Lipos do what we rc'ers call puffing. No matter how well you handle them or take care of them they start to swell or "puff" over time. Lipos usually need to be discarded about every two years even though they still hold a good charge they'll be swollen up round like a basketball. Before discarding I always cut off both battery leads and drop the battery in a five gallon bucket of salt water for about a day to truly kill the battery. Otherwise it may burn the recycle center down when they crush it and the cells short.
Lipos have great power but with great power comes greater responsibility.
Tom
