05-02-2013, 01:35 PM
The PRR did things in unique ways -- however, my understanding continues to be that the lights on the smokebox are markers, those on the pilot beam are class lights (or the use of the lights on the smokebox may have changed when the lights on the pilot beam were removed). Here's a photo of a PRR freight loco after the permanent class lights were removed from the pilot:
![[Image: prr4192.jpg]](http://www.northeast.railfan.net/images/prr4192.jpg)
Note, however, that you can see the tender rear in this photo, it continues to have semi-permanently mounted markers. I can think of two explanations for the lens colors in the RR Museum of Pennsylvania photo: either the museum mounted the lenses in error, or the function of the lights by the smokebox front changed when the lights on the pilot beam were removed from freight locos. As a near-charter member of the PRRT&HS (at one point, I think Buchan was about to toss me out until he saw my membership number), I can't recall any clear explanation of what may have changed when the lights on the pilot beam were removed from freight locos. If Dave has a good reference, that's even better!
The exact use and position of the class lights/markers on PRR locos doesn't change the general situation of headlight/marker color above, of course. It does point out how usage in areas like this was not standardized on US railroads.
Note, however, that you can see the tender rear in this photo, it continues to have semi-permanently mounted markers. I can think of two explanations for the lens colors in the RR Museum of Pennsylvania photo: either the museum mounted the lenses in error, or the function of the lights by the smokebox front changed when the lights on the pilot beam were removed from freight locos. As a near-charter member of the PRRT&HS (at one point, I think Buchan was about to toss me out until he saw my membership number), I can't recall any clear explanation of what may have changed when the lights on the pilot beam were removed from freight locos. If Dave has a good reference, that's even better!
The exact use and position of the class lights/markers on PRR locos doesn't change the general situation of headlight/marker color above, of course. It does point out how usage in areas like this was not standardized on US railroads.