PRR steam locos

I believe the lower set on the pilot are actually markers and the class lights are the upper set.

I could be wrong...

Steam Crazy posted:

Many PRR steam locos have two sets of classification lights on the front end, two atop the boiler and two on the pilot.  Does anyone know the function of the set on the pilot?

You might try searching the Pennsylvania RR Technical & Historical Society.

John, I believe markers lights designate the rear of a train.  Hot Water, thanks for your suggestion.

John

Steam Crazy posted:

John, I believe markers lights designate the rear of a train. 

Right. So,,,,,,,,,,if the locomotive is backing up, then the front becomes the "rear of the train", and thus red marker lights would be displayed to the rear.

Hot Water, thanks for your suggestion.

John

For those that may be remotely interested, back in late 2016 Ed Rappe posted about an article on PRR class lights by Elmer Steurernagel that was published in PRRT&HS’s The Keystone Vol 35, Number 1, Spring 2002.   Ed listed an overview of the changing standards. 

• 1922 - PRR adopts a cast 2-piece (claw foot/rotating 4 lens helmet head) fixture for class and marker lights on steam locomotives 
• 2 pair of marker light fixtures - 1 red lens, 3 amber lens

• • 1 pair mounted on the pilot beam
  • 1 pair on the tender deck corners
• 1 pair of classification light fixtures mounted  on the smokebox - 2 green lenses, 2 white lenses

• 1929 – shops ordered to remove classification lights from locomotives assigned to yard and freight service (except M1/M1a's and other freight locomotives regularly assigned to passenger service
• 1935 - shops ordered to replace inside and rear facing amber marker light lenses on engines and tender with blank discs - leaving 1 red and 1 outside facing amber lens
• Dec. 1939 - shops ordered to relocate tender marker lights on K4s and I1s Kiesel tenders to rear shelf platforms - effected classes include 110P75, 110P75a, 130P75, 130F82a
• June 1940 - PRR ceases to use the train classification rule (extra, second section following) - shops ordered to remove classification light fixtures from locomotive smokeboxes
• June 1942 - PRR adopts smaller oblong (tombstone) marker light fixture for application to smokeboxes in lieu of pilot beam mounted marker lights.  In their housing are two lenses yellow above, red below, not all locomotives were re-equipped with the new markers
• Aug 1946 - PRR adopts a smaller single red lens round "bulls’ eye" marker light fixture for use on smokeboxes.  This is the most common marker light fixture seen on postwar PRR steam locomotives – however many with tombstone markers retained them until dropped from the roster

Thanks guys, I "get it" now!

John

What HW said, if you're backing up, you may want markers on the front.

Markers were required to be displayed at the "rear" ie opposite direction of travel.   If a loco was running tender first and light, it would have to display red markers on the pilot beam.     Marker ligthts are not based on physical location, but to protect direction of travel.

Yes, markers denote the rear of the train.