I think the only way anyone's going to be able to help you is if you can scan the pics and post them on here - a description is unlikely to cut it!
Altoona was the PRR's main locomotive works, so it would make sense for them to be PRR Locos.
Someone gave me some original mounted photographs from what lools like the turn of the century. Two of them look like original builders photos of early PRR locos. On the back is a stamp that identifies the photographer as H.G. Colyer, Altoona, P.A..
Can anyone give me any info on these..... Thanks Jerry