Yea, you can do it.  On mine I did rewire the loco as the harness coming from it was a little short when connecting to the Vandy.

So Bachmann how about a 2-6-6-6 C&O Alleghany?  You have done the 2-6-6-2's so it would make sense.  No one has ever made it in plastic (brass yes) and it is a much needed loco.  Anyone else agree??

If I remember correctly, the TCS website shows how to install a decoder in these engines.  The colored wires are the same on the Digitrax one.  The blue, white, and yellow wires control the lighting.  They may need to be speed matched but since they are all the same mfg they may just work straightup with each other.

So Bachmann came out with the 2-6-6-2 H-5's a while back and I own a couple of them.  The newest offerings of the 2-6-6-2 is an H-4.  I really like both locos.  Of course there are a few external differences with one of them being the tender type (USRA vs Vandy).  I have noticed the 2 loco types run differently.  The older H5 is not as smooth and is much louder when compared to the newer H4.  My H5's have decoders installed also but that doesn't seem to be what is causing the noise.  Both H5's I have are much louder than the four H-4's.  There is both an audible and visual difference between the 2 loco mechanisms. 

So this of course leads to a few questions and maybe the "Bachmann" can answer these.  First off, has anything changed between the mechanisms which makes the newer H-4 operate much better (are the engine's (meaning geared trucks) different)?  I haven't tried this but will the H-5 loco shell fit on the newer H-4 chassis?  I am open to wiring the older H-5's similar to the H-4's and have the decoder in the tender if I can get a smoother running loco. 

Would Bachmann be willing to swap out my older H-5 mechanisms for the newer H-4's if I paid a nominal fee, if they were/are available, and swapping shells would work?  This option seems easier and cheaper than having to buy all new H-4 locos to make my H-5's better. 

Anyways, any help would be appreciated.  Thanks.