I have an AHM HO model PRR J1a as well as a couple Westside brass and a BLI J1a's. The sand pipes on the AHM model are different from the other three and everyone I have seen online and in books are the same, except #6475, it has the ones like the AHM model. Can anyone elaborate on this and tell me why it was different and were any others the same as the AHM brass model. I was going to modify the AHM to be like the others until I saw the 6475, now I want to be sure it is correct before I cut anything and possible ruin the model.

Certain PRR class J1 locomotives had the sand pipes under the boiler jacket while others had the sand pipes exposed externally above the jacket during their service life. If you are attempting to model a specific road number J1 or J1a prototype you will most likely need to determine the sanding pipe issue on the road number you wish to model based on actual photographs and records. If you have an AHM HO scale brass model with the external pipes, they are considered more rare than AHM models with the usual piping arrangement.