Hello Tim,
I think, first you have to think about, what you want to do.
Look at our FAQ, points 1 to 3 [CLICK HERE], if you want RC-Locos or with transformer (older system, but with more locos).
For the old system you need brass LGB track (RC-Locos also could go there), for RC-locos allone the plastic track is a little cheaper.
The wagons/cars are for both systems.
What do you mean with »engineers train«?
A working train or a steam loco/train?
I also think, for customizing Playmobil trains/locos/wagons, LGB parts are too expensive and perhaps too sensitive. 
You can build customs with Playmobil parts (of lorries, cars, doors of houses,...), plastic plates and other useful plastic parts (like plastic bottles,...).
@playmofire:
I think the 4010 loco is not a »Taurus« (
the »Taurus« is an austrian loco, built at Siemens/Germany), it's a little bit different from it (look at the lights, they are vertical, 4010 has horizontal lights).
The number is printed on the 4010 (BR 182 would be the same as the »Taurus«): 
152 019-1 => 
it's a »Baureihe 152« [CLICK HERE!]zugpferdchen