Do they have to be an EXACT match (as in, you are repairing a BLI engine)?
If they just need to be very close for a new tender, ...
Is Fine-N-Scale still making their decals? (They have them on their website).
About 1000 years ago, when I scratchbuilt my T-1, I used Fine-N-Scale PRR Passenger Car Decals, item #2600.
The set includes various widths of stripes in a good color for the T1 tender. The long "PENNSYLVANIA" text was a good
match from that set also.