I have fitted DCC decoders to a fair number of so called ready locomotives over the last few years and a word of caution to anyone contemplating fitting one themselves. Initially DC test and run in the loco if required. Absolutely always test on the programming track after fitting a decoder and if the programming tool/software says there is short cct (or 'short cut' on my Lenz system) believe it otherwise smoke release from a decoder is likely when placed on the running track. It appears to me that locomotives factory assembled with blanking plates/plugs fitted are not thoroughly tested, a number of faults can be hidden, here is some I have found, initially by smoking a decoder or two. 1) crushed damaged wires - e.g. Heljan railbus 2) wires swapped at connector - e.g. Red/Orange or Black/Grey- e.g. Heljan railbus 3) chassis wired with brown wires, motor wired red and black, the red and black then being wired in the correct position at the decoder socket for track power. So track power and motor leads swapped at the socket. e.g Model Rail / Kernow Sentinel 4) pair of tender to loco 2 pin connectors swapped at tender, thus swapping motor and track wires at tender. Wires too short to swap connectors over so fixed by soldering within the tender e.g. Bachmann Ivatt 2MT. 5) a manufacturers own decoder needs tape to prevent shorting against metal cradle lugs e.g. Hornby Peckett. 6) light connections swapped at decoder socket e.g. Heljan Hunslet 05 The general standard of the hand soldering is very poor across many makes of models and some decoder manufacturers. We pay a lot a money for these models and fixing them is time consuming for those who can do it and expensive for those who cannot. If any manufacturers are reading this please help us and we will buy more!