What you've got there, Mick is the 4011 version with working lights and the 4119 centre section originally designed to go with the earlier 4016 and 4018 versions which hadn';t working lights.
The centre section is a bike/car carrier (the Playmobil "Smart" car fits in nose first) but was never a big seller. It's a bit unstable and very heavy and tends to kill the performance of the RC motor, as well as gobbling batteries.
Converting to track power is easy. Buy a Playmobil track powered motor off, say, plamoking on eBay. Remove the RC motor. Carefully align the other motor in its place and mark where it goes. Put some heave duty double-sided sticky tape on the motor and fit it in place. Place train on track and add power.