Purpose of 2 green Steam Locomotive Lights?

They're classification lights.

White. Indicated an "extra" train not shown in the timetable, Green. Indicated that, while the train displaying the lights was a regularly scheduled one, a second section was following behind it.

The green lights on a scheduled train would indicate a second section is following; white light would indicate an extra train.

On my layout, the "second" section would actually be the same train - different lap!

Neil

I guess if you use the white lights, you need to follow it with another train.

Red ones indicate you're backing up.

Truthfully, I could never understand the steamers with red class lights...

No, white lights indicates that it is just an extra train. The green class lights would indicate that a "second section" was following.

Right extra, but there must have been another one.

What color would they be if the train was a scheduled  train with no extra? 

They would be off.

I forget where I found this on the internet but this might help:

Markers, Class Lights, and Signals

The 1939 edition of The Consolidated Code of Transportation Rules was used for the following diagrams and rules. This rulebook was used by the:
- Great Northern
- Northern Pacific
- Spokane, Portland, and Seattle
- Union Pacific
- Milwaukee Road
It should be noted that not all of these railroads used all of the forms of marking shown below. Also, other railroads used different rulebooks but you will find that the wording of those rulebooks in most cases closely coincides with this rulebook and the wording is often verbatim across different rulebooks.

Markers

The rulebook definition of a train is:

An engine with or without cars, displaying a marker.

Rule 19 states:

The following signals will be displayed to the rear of every train, as markers, to indicate the rear of the train.

Markers are not simply "tail lights" to prevent a following train from running into the rear end of a preceding train. Markers designate the rear end of a train. Railroad employees need to know that a train is complete. They need to know that part of it has not been left behind either on purpose or accidently. Crews on other trains that must wait for this train need to know when it has arrived in its entirety so that they may then proceed with their own train. Track maintenance crews need to know when a train has arrived in its entirety so that they can then work on the track. Tower operators and station agents need to know when a train has arrived in its entirety so they can report this occurance to the dispatcher.

In today's world where the color red is universally used to mark the rear end of automobiles, trucks, and trains it may seem strange that in 1939 some railroads used green flags to mark the rear end of their trains. Even stranger, they used green only in the daytime and used red at night. But the seeds of the red-only-rear-end are already planted int his 1939 edition of the rulebook.

Rule 19(A) states:

A train not equipped to display the required markers will display a red flag by day and a red light by night , to indicate the rear of the train.

(The grey Marker lamps in the following diagrams depict unlighted lamps).

The above diagram depicts the rear end of a passenger train, but the Markers would be the same if it were a caboose or the last freight car of a cabooseless train.

The diagram below shows how the Markers would be applied in exactly the same manner to the steam locomotive tender if that loco was running without any cars or if that loco was pushing on the rear of a train.

The diagram below shows how the Markers would be applied to the front of a steam locomotive if that locomotive was running backwards without any cars or if that loco was running backwards while pushing on the rear end of a train.
Note that the headlights are extinguished.
Note that on the front of a steam loco the Markers are the lamps or flags mounted down low on the pilot beam. Do not confuse these low Marker lamps or flags with the higher lamps or flags which are Class Lights that are described later.

Note that in the left hand drawing of all three diagrams above, the mere presence of the Marker lanterns during the daytime constitute Markers even when they are unlit.

Class Lights and Signals

During the long period that railroads were operated by the Timetable and Train Order method the train Schedules were published in the employee's Timetables. These schedules were the actual operating authority for those trains. That is, the Timetable authorized those trains to use the mainline, between the stations listed, at or after the published time of day. Those trains and other trains operated based on these schedules and rules Trains operated in respect to each others' schedules by a collection of rules that kept the trains from colliding.

Trains that were operating on a schedule that was published in the employees' Timetable were called Regular trains. Trains that were operating solely by Train Order authority and did not have a timetable schedule were called Extra trains.

Regular trains were one of three classes. Naturally enough they were named; First Class, Second Class, and Third Class. Some railroads also used a Fourth Class. Since the purpose of this discussion is to explain Class Lights and flags, not the nuances of Timetable and Train Order operations, it will be sufficient to say that these different classes exist, and that they do exist is why the about-to-be-discussed lights on locomotives are often called Class Lights. However the proper term for these lamps and flags is Signals.

A Regular train, one authorized by the employee Timetable Schedule, would normally have no Signals on the front of its locomotive. If the Signal lamps are of the permanently mounted type then they would be unlighted. The only light on the front of a Regular train would be its headlight and even that would only be illuminated at night. In the daytime the front of a locomotive on a Regular train would be entirely unlighted. The daytime headlight-on rule did not exist on most railroads until the second half of the 20th century.

Sometimes a Regular train would have so much express or so many passengers or freight cars that it could not be operated as a single train. It must be operated as two or more trains. These multiple trains of the same schedule are called Sections. Since the operating rules that keep trains from colliding and that allow track maintenance personel to safely use the mainlines are based upon the timetable scheduled trains, there needs to be some method of telling other crews and employees that there is more than one section of this train. That method is called Signals.

If a scheduled regular train is running as more than one section then all sections except the last section will be given a Train Order instructing them to "Display Signals" for a following section. The last section will not be given this Train Order so it will run without signals displayed. When crewmen of other trains and other employees see a train go by displaying signals they know by the rules that this is only a section of the train and that another section will be following.

Rule 20 states:

All sections except the last will display two green flags, and in addition two green lights at night, in the places provided for that purpose on the front of the engine.

Note that the flags must remain displayed even at night. Also that these green flags and lights always go on the front of the locomotive, not necessarily the end that is leading in the direction of movement.

The green flags/lights for the purpose of denoting another section is following are displayed high up on the locomotive not down on the pilot beam where the Markers went. Note that there are no markers displayed since this is not the rear end of the train.

The diagram below is looking at the front of a locomotive that is running backwards moving away from the viewer. Since this would also be the rear end of a light engine move (engine without cars) or the rear end of a helper loco pushing on the rear of a train, these drawings also show Markers displayed on the pilot beam per rule 19.

If instead, the locomotive was running forward either light or pushing on the rear of the train then the green signals would still go on the front of the loco as shown in figures 10 and 11 above and in addition the Markers would be displayed on its tender per rule 19 Figures 2 and 5.

Only Regular (Timetable Scheduled) trains can run as multiple sections. Thus only Regular trains can display green flags or lights as signals for a fllowing section. Trains that are not authorized by a Timetable Schedule are called Extra trains. Extras are authorized solely by Train Orders.

Rule 21 states:

Extra trains will display two white flags, and in addition two white lights at night, in the places provided for that purpose on the front of the engine.

Rule 22 states:

When two or more engines are coupled, each engine shall display the signals as prescribed by rules 20 and 21.

That means if there are two or three engines pulling the train, all of them will displat the appropriate signals for that train. It also means if there are two or three engines pushing on the rear end of a train, all of those engines will display the appropriate signals for that train. But only the last engine on the rear of the train will display the Markers for the train.

The 1959 edition

By 1959 the name of the book had changed to The Consolidated Code of Operating Rules and several more railroads had signed on to it use, including the roads that eventually made up the Soo Line.

The display of Markers under Rule 19 remained the same except for the addition of a Rule 19(B) which stated:

When the rear of a train is equipped with built-in electric markers they must be lighted by day and by night. The requirement that markers display green to the front and to the sides will not apply.

Obviously this is a nod towards the now ubiqitous diesel-electric locomotives. Similarly Rule 20 and Rule 21 were modified to eliminate the green and white flags, acknowledging the brighter lights of the period.

Rule 20. All sections except the last must display two green lights by day and by night on the front of the engine.

Rule 21. Extra trains must display two white lights by day and by night on the front of the engine.

Rule 22 requiring that all engines on a train display the proper signals for that train remained in effect. But the definition of an "Engine" was changed to read:

A unit propelled by any form of energy, or a combination of such units operated from a single control.

So where as multiple steam locomotives were each required to display signals, only the front unit of a multiple unit diesel should display signals because it is only "one engine". In addition an exception was added to rule 22, in block signal territory, dropping the requirement helper engines display signals for the train they are pushing.

Looks like the diagrams didn't paste correctly.

No. Many railroads operated ALL their freight trains as "extra". Passenger trains where a completely different story. On some branch lines, the only freight train to operated every 24 hours might be an "extra", thus there would NOT be "another one". Any passenger trains would have been listed in the timetable.

The Lionel 1615 0-4-0 steam switcher (which has red class lights) being a case in point.

I don't think red was an option on most, if not all steam locomotive class lights. 

IRM's 1630 class lights (Adlake) are white with internal green lenses that can be moved into position using a lever on the light housing. 

Rusty

Red was legitimate if the locomotive was backing down the main line; it is essentially

the end of the train, and, like a caboose, needed red markers (not "class" lights at this

point - class on front, markers on rear).

I typically remove or turn off the LED's on my steamers' class lights and tender markers.

Usually the wrong colors, or too bright or, mostly, just inappropriate. Very Christmas-

tree, toy-looking, and were typically Off in the real world, anyway.

Real (RR) world? Maybe take a look occasionally.

The 1615 evolved from the pre war 701 which was a B6 shifter. The shifters and some road engines had lights mounted on the pilot beam. I believe these were red to indicate an engine running in reverse. You can also find images of early PRR engines with pilot beam lights and class lights above the headlights. 

I think Lionel just took some liberties in repositioning the reverse lamps.

Hopefully someone more familiar with PRR practice will chime in.

Pete

Class lights Pete, I know about the markers down low, but those would normally be off I expect in normal running.

I had to do some searching but did find a number of pics of PRR engines with lights both on the pilot beam and high on the smoke box. Most seem to be dated in the late '30s.

I assumed they had different functions???

Pete

My understanding, which may not be totally accurate, was the class lights were up high.  Any lights on the pilot beam are probably the marker lights.

 I was just looking at my Modern Diesels book by Brian Solomon. On page139 is a modern SD70M-2 in CN with class/marker lights up high next to the number boards. They were off in the photo. They appear to be red?

 When would they be on? It's the only version I noticed that had these lights? Didn't know they were still in use?

Ive been reading up on this every now and then. I cant quote my sources because I don't remember exactly where I read what, but here goes, what I "know"-

The class lights(up high)- Some engines did have a red lens lever also, as soon as they are red they are considered markers. I assume manually changed lenses weren't used up high because it was easier to light and place a marker lamp for reverse travel which often wouldn't be too far. Some railroads(S.Fe?) insisted the red couldn't be seen up high so foremost the headlight must be dimmed, but I think that might be diesel era rules.

Green and red mixed markers(and "class")- Canadian(P?) double track markers showed green to the inside track red to the outer. I would think this would apply to a reverse running loco too. Around Christmas engineers all over were known to occasionally mix red and green on forward running locos. My 2037 came that way. Mistake or customized? I don't know. It was a gift from my Gramps. A few years ago I lost the red one. I replaced it with another green one "knowing" I was right . Since reading about this mix, I have plans to put a red one back in .

For those rivet counters with red "class markers" Just lock it into reverse use a low watt headlight and run it. Psst. Hey did you ever consider how prototypically wrong it is to back up without the red markers on the boiler end of other locos?  

And the switchers? They spent a lot of time backing so the red there makes sense to me.    

Clearly Lionel wanted to add some color and 'class' to an otherwise plain, black front.

Anyhow, that's my take on it and I'm sticking to it.

The rules could be satisfied by placing a red flag in the knuckle or hanging a red lantern on the front of the locomotive if necessary.

Switchers working within yard limits don't require markers or class lights.

Rusty

Until a knowledgeable PRR fan weighs in I am going to contend that the lamps mounted on the pilot beam were markers and were always red. PRR did use them on their yard engines and apparently some road engines for a period of time. I finally came across a color photo that bears that out.

I think it might explain why pre and post war Lionel 0-6-0s and 0-4-0s used red jewels in their "class" lights even though they are misplaced. The B&W photos that show pilot beam lamps are dated late '30s which is also the time frame the the pre war 701 was created.

Pete

Makes sense.  I believe those class lights will rotate and display white as well, I've seen some that do that.  Some had changing lenses to change the colors.  I have one steamer that has the pilot mounted red lights and red class lights.  I'm thinking of changing the class lights to green ones as they seem to be more logical.

Would love to see MTH and Lionel include these green/white classification lenses as well as red back up markers on appropriate steamers in their Premier models.....some are so obsessed with rivet counts and other details....I for one would like more correct lighting....

Wouldn't it be cool to have green/white LED's and the ability to change the color from the remote?   Of course, I'd like to see other lighting like ground lights, step lights, etc. that are present on many locomotives.

I agree...especially with the lower cost of LED's and the high cost of these engines....I don't think it's asking too much..

Just my opinion, but I would settle for a simple on/off switch, so I could shut the front class lights off, especially if the manufacturer installed the "wrong color". I'ld also like an on/off switch for the real marker lights. 

At least with the later MTH 2.0 and 3.0 steam locomotive models, the class lights can be turned off with the DCS Hand Held.

I have played with three color LEDs, blue, green, red hoping to hoping to able to change colors and even make white with all three turned on. Unfortunately the ones I have are embedded in a non difuse clear lens. You have to be looking straight at the top of the lens to see the color or any mixing, plus they are 5mm LEDs and too large for use in class lights. You might be able to fiber optics in class lights located in front of the smoke box but I don't think that would work with top mounted lights as the light eminates from the end of the fiber. Color change would be made using white light and a rotating color filter.

Who knows, in five years the technology may allow this to happen.

Pete

There are 3mm multi-color LED's, but the class lights frequently have the 2mm ceramic base LED's in them, and that's all the room there is in them.  The ceramic base LED's are very small and don't have the big chunk at the other end.

Ceramic Base 2mm LED.

With many of the Legacy locomotives, especially the newer stuff, you can turn the class or marker lights on and off.

I agree...especially with the lower cost of LED's and the high cost of these engines....I don't think it's asking too much..

I find it astounding no one produces fully functional class and markers, seems like an easy enough option to design in compared to some of the elaborate smoke options.

The technology isn't the issue here, it's getting the manufacturers to actually do it.

S-Helper installed classification lights in their F7 diesel locomotives that could be remotely adjusted to off, white, green, or red. We'll have to see if MTH continues with that feature.

Class lights on diesels would be fairly easy to do with fiber optic light pipes. Not nearly as easy on steam engines.

Pete

With diesels, you can normally just drill the hole in the proper place and use a standard LED, no fiber required.   For steamers, you need the light fixture, makes it a lot harder as you say.

John are you saying you know of three color LEDs that will fit? Single color is trivial but three colors with an off mode will require more than a hole and single LED.

Pete

If you will go to the following website, you will find the answer to all of your questions about the PRR marker and class lights:

http://prr.railfan.net/documents/

1.) Scroll down to "Management & Operations" to find the PRR Rule Book (circa 1925) pdf file.

http://prr.railfan.net/documen...BookOfRules-1925.pdf

2.) Click on it and wait for it to load. Naturally it is a big file and takes a while to load.

3.) Scroll down to page 23 and start reading from there.

4.) You may want to save this file for future reference.