1982 Chef Boyardee Diesel Hustler

[SteamGene]

It is physically possible to run brass and nickle silver together.  Code 100 brass and code 100 nickle silver are the same height.  Brass track actually conducts electricity better than nickle silver, however, brass tarnishes faster and is a harder to clean.  I've found some brass track as I'm building my new layout.  When I find it, it gets set aside so I can strip the ties for possible other use and recyle the brass. 
If your son is really serious, you want nickle silver track and knuckle couplers (Kadee and clones.
Gene

[JM]

The Bachmann track -- ""EZ Track''--- has molded on roadbed, black or gray in color and it is interchangeable,  there are other brands like Life-LIke that won't work with Bachmann,  just stick with Bachmann track and you'll be fine. Brass or nickle steel are compatiable.

[jayl1]

Gene is correct with compatability.  Stick with nickel silver.  Should you use Bachmann EZ track, go with the gray roadbed (base).  That is nickel silver.

[SteamGene]

In 1982 there was no EZ-track. 
Gene