B&O 466292 in the Sentinel Service paint scheme was photographed by Walter E Frost in Vancouver, BC, on June 13, 1954 (re-weighed and repacked at WA in 9-53)
http://searcharchives.vancouver.ca/b-o-baltimore-and-ohio-railway-co-box-car-466292
and was also photographed by Hubert E Mills at Squamish, BC within a few days of Walter’s photo.

PRR X29 # 52569 in the Merchandise Service scheme was photographed by Walter E. Frost in Vancouver on October 4, 1953 (re-weighed at P129 in 3-50 and repacked 4-5-53 at what looks like “WSC”).
http://searcharchives.vancouver.ca/pennsylvania-box-car-52569
Another PRR Merchandise Service X29, 505797 (re-weighed at P129 1-53, repack stencil not readable in the photo), was photographed by William H. Hewlett at Squamish, BC in August 1954.

As these photographs are one to two years after my modelling period, my question to the B&O and PRR experts is: What is the earliest date cars from these specialized services were re-assigned to the general box car pool and would, therefore, possibly be seen as far afield as Southwestern British Columbia?

In the 1950s, it was a common practice for the CPR to send empty US box cars at Vancouver to the PGE in Squamish for lumber loading to US destinations.

Any assistance is greatly appreciated.

Greg Kennelly
Burnaby, BC