Ultra realistic with loco valve pilot cam box

I've never been a stickler for extreme accuracy in representation of all the details on a loco, as long as the overall "look" of the loco was good.  I accept that such details are often glossed over by manufacturers because they have to make casting models, etc. that willb e used for many similar locos, that actually had variations in such details.  As I understand it cam boxes and valving varied greatly among otherwise very similar locos, etc.  Someone like Lionel or MTH pretty much has to lock in one design in their castings even though, in some cases, loc number 929 might have had one version while 1019 had another, while otherwise the same loco design, etc.

From what I have read, I was under the impression that the cam boxes and valving were one thing that was often changed over time, among locos in a long production (i.e., during the 20 year product of all 225 Baldwin XXXXs the cam box design was tweaked several times from first to last) and for indidivual locos that were upgraded for power, or more often, for improved economy, over time, a new cam/valve arrangement being done.  I know, for example, that playing with the valve timing (i.e., cams) and changing out the valving was a favorite trick of Chapelon, the French "genius of steam" who often would fine-tun existing locos to improve their HP and economy by up to 100%. 

fmbugman,

A lot depends on what era you are modeling, as MANY railroads removed the Valve Pilot arrangements toward the end of the steam era. For example, I model the early through mid 1950s era, and MANY of the Valve Pilot arrangements have already been removed, due to the higher maintenance required. Plus, if an Engineer didn't know how to "properly operate" his motive power by then, it was too late.

Ditto Lee's position about the overall impression of a train rather than it detail accuracy.

However, there is a detail that irks me when it's not included, and that is the tender backup light. That tender light is the only telltale indication that a train has a command to backup.