Unfortunately this does not allow installation of most of the current decoders with the NMRA plug because plugs are too thick. This results in a crammed installation which may work but is not desirable or reliable. While I have seen folks attempt to do this, the installation is highly compromised problematical and unreliable . Observe caution when handling or working on this loco. Some units slow down unexplainably in tight radius turns.
Solution is to add more solder to decoder pads that engage in frame.
Tight internal vertical clearance allow minimum space for NMRA plugged decoders. Return to dealer or Bachman. Plug assembly between loco and tender are very delicate and wires can pull out easily. Thin decoders like Lenz 103XF and NCE D102 will also work on several units. Gear box assemblies screws overtightened when assembled at factory causing gear box flanges to crack on some units witch then causes rough running.