Most recent Hornby and Bachmann Steamers and Diesels are excellent on dcc sound. All have multiple pickup systems and good quality can motors which makes them ideal for sound conversion.
The only difficulties encountered when converting these models to sound is finding a suitable location for both speaker and decoder. Preferred decoder for these is the Loksound V4 and Loksound V4 Micro. Often space is particularly limited for speaker location to get optimum sound levels and this usually means removing the decoder socket and hard wiring the decoder or making modifications to chassis or shell.
Below you can see some example test runs of Hornby locos running on dcc sound