Hi, I was just messing about with your mod and I ran into a crash. I was in sandbox mode and had built a straight stretch of rail, I placed a train bulider and was making the Super Locomotive from Editor Extensions.

The mod Train construction site (0.2.16) caused a non-recoverable error.
Please report this error to the mod author.

Error while running event trainConstructionSite::on_nth_tick(5)
trainConstructionSite/src/traincontroller-builder.lua:321: attempt to index a nil value
stack traceback:
trainConstructionSite/src/traincontroller-builder.lua:321: in function 'buildNextTrain'
trainConstructionSite/src/traincontroller-builder.lua:145: in function 'updateController'
trainConstructionSite/src/traincontroller-builder.lua:460: in function 'onTick'
trainConstructionSite/src/traincontroller-builder.lua:473: in function <trainConstructionSite/src/traincontroller-builder.lua:472>

Also, when in freeplay mode I can see the Editor items in the Transport Logistics tab when they should be hidden.

Note to self: can be fixed by configuring the super locomotive as an electric train https://github.com/voske123/FactorioMod-trainConstructionSite/blob/master/prototypes/modded-final-fixes.lua

This is fixed in the new release.