The mod Railway Motor Car (0.6.0) caused a non-recoverable error.
Please report this error to the mod author.

Error while running event railway-motor-car::railway-motor-car-key (ID 309)
The mod JD's Speed Limits (1.1.2) caused a non-recoverable error.
Please report this error to the mod author.

Error while running event jd-speed-limits::on_train_created (ID 81)
jd-speed-limits/scripts/train.lua:94: attempt to index field 'burner' (a nil value)
stack traceback:
jd-speed-limits/scripts/train.lua:94: in function 'calculate_direction_power'
jd-speed-limits/scripts/train.lua:85: in function 'calculate_power'
jd-speed-limits/scripts/train.lua:64: in function 'calculate_derived'
jd-speed-limits/scripts/train.lua:21: in function 'register_train'
jd-speed-limits/control.lua:45: in function <jd-speed-limits/control.lua:39>
stack traceback:
[C]: in function 'create_entity'
railway-motor-car/scripts/use_equipment.lua:115: in function 'mount'
railway-motor-car/scripts/use_equipment.lua:212: in function <railway-motor-car/scripts/use_equipment.lua:197>

I also reported this to the other dev
Steps to reproduce attempt to use the railway motor car with Jd's speed limits installed

The issue appears to be the fact that the RMC is not a burner and uses equipment grid electricity

Also if you haven't already done it adding quality acceleration and top speed would be nice