Mike Bett said:
Can any one tell me if the 20851 has a DCC interface? As this engine has two motors I assume it would need a 55027 chip.
Mike, the 20851 was discontinued the year before LGB introduced their MTS system. As far as I know it wasn't fitted with any form of interface. That said, it's a very easy loco to rewire for MTS, especially if you use a DCC chip with screw terminals such as the Massoth XL. There are examples of rewiring its predecessor, the 2085D in the DCC decoder fitting thread. The 20851 is the same except there is no need to struggle fitting a separate motor feed as the 20851 should have a 4-pin "D" gearbox, not the older 3-pin type. Feel free to PM me if you need more details.
By the way, the 55027 is intended for much more recent locos which have the latest style of interface plug. The same plug is now supplied as standard with the Massoth XL which is rather cheaper.