The Keystone Set question

[Edward2P]

My brother got The Keystone PRR train set, and he wanted me to ask a question because it was bugging him.  It comes with 3 coaches, a combine, a coach, and an observation.  Well, he was wondering why the combine and observation had 6 wheel trucks and interior lighting, and why the coach only had 4 wheel trucks and didn't have interior lighting.  Why is this?

[Guilford Guy]

The Coach is loosely modeled after PRR's P70 coaches. The P70's were used in commuter service, and did not demand 3 axle trucks. The Combine and Observation are pretty much off the shelf Bachmann Cars, without the slight changes on the coach to look PRR-ish. The NYC set is similar, the Combine and Coach has 2 axle tracks, while the observation car has 3 axles.

[RAM]

I would like to say that the coach does have lights because it is a sleeper. My guess is that it is a cheaper car.  I better grow up before Bachman blocks  me.

[the Bach-man]

Dear All,
GG is correct.
Have fun!
the Bach-man