How A Diesel Locomotive Works

Is it possible to fit a DCC chip to old Hornby OO gauge locomotives?
I have a large collection of 1970s Hornby locomotives gathering dust in my dad’s attic, but am currently building a DCC circuit having just bought a new train set for my son (well, that’s my excuse). Is it possible to fit DCC decoders in these old locos (mostly tank engines, but there are also a couple of diesels and a Pacific); if so, how difficult is it, what considerations do I need to take into account when working on them, and is there anything else I should know?
Retro fitting DCC can be a daunting task. In the end you will be able to enjoy your trains on your (son’s) track.
Check this site for more information:
http://www.digitrax.com/faqtransponding.php
Modern Marvels: Freight Trains [Part 3/5]

