The mod Train Control Signals (1.0.4) caused a non-recoverable error.
Please report this error to the mod author.

Error while running event Train_Control_Signals::on_train_changed_state (ID 24)
Train_Control_Signals/script/train_control_signals.lua:16: attempt to index local 'fuel_inventory' (a nil value)
stack traceback:
Train_Control_Signals/script/train_control_signals.lua:16: in function 'train_needs_refueling'
Train_Control_Signals/script/train_control_signals.lua:99: in function 'handler'
core/lualib/event_handler.lua:47: in function <core/lualib/event_handler.lua:45>

this occurs when using the Railway Motor Car mod and arriving at your destination in automatic mode.