Yes Mark, if your 2-10-2 has the standard 10-pin DCC interface socket and your XLS has the correct sound files for the loco, it should be just a matter of wiring the Massoth 10-pin harness (supplied with the XLS) onto the decoder board and then just plugging it into the loco socket. You'll have to follow the Massoth manual carefully to get the plug harness wired up to the screw terminal strips on XLS, it isn't tricky but check it several times to be 100% sure you've done it right!
Of course you'll also need to install the speaker (which is just a matter of two or four retaining screws and washers) and then plug the two-wire harness from the speaker into the socket on the XLS.
Then it should, in theory, work!
If you haven't yet bought your XLS, may I suggest that you talk to another Mark on here, "Muns", who runs Garden Rail Outlet and should be able to not only supply you with the decoder but also give you as much help and advice as you might need..... usual disclaimer, I have no connection with Mark at GRO except through being a fellow GSC member and very happy customer, and of course (as they say on the BBC) "other Massoth dealers are available"....
Jon.
