Identify "old" passenger train

[scalawag37]

I am not experienced at train following, but I spotted an usual passenger train
pass nearby today and was wondering how to identify it.

It was about 1300 CST, 6 March 2011 in Marfa, Texas which is about 1/3 of the distance
from El Paso to San Antonio.

The train was headed East and was too far away for me to see any identification.
Two of the typical SF yellow engines were pulling 3 orange/black passenger cars
each with some sort of black dome on top, followed by about 7 regular passenger cars
also orange as main color.  All cars seemed to be of a 1950s/1960s type or replicas.

Any ideas?? 

Thanks, Vern

[Avianwatcher]

Could they be vintage KCS cars?    It also may be a special of PV's on an excursion?   

[BaltACD]

Sounds like one of the UP's Business Car trains, with several 'foreign' cars along for the ride. 

It my be pursuing a business opportunity with some shippers or some other opportunity with the 'foreign' carrier.

[Falcon48]

If all of the cars were "orange", they aren't UP business cars.  All of the UP cars are yellow.