Class Lights Use, Especially Green ("Section Following")

[C855B]

... The eastbound Empire Builder ran in two sections at least once.  I saw it, at the Pasco station, and between the two sections it had twenty-some cars.  I don't remember the exact number, but somewhere in the mid twenties.  The first section had SDP40Fs, and the second F units, which were seldom seen after the new units entered service.  That's the only time I ever saw a train with green class lights. ...

Green classification lights (and green flags) are an artifact of timetable operations, so I guess it would make sense that a passenger train split in two would carry markers. I recall... barely... seeing a few back in the '60s when SP was still adhering to a published timetable with numbered freights over the Tehachapis. Never saw green flags, but markers, yes. I don't remember when they dropped numbered trains from the timetable, but in running the railroad after the policy change but before the new timetable was issued, everything was operated as "extra" trains, displaying white markers. I moved away from the area shortly after, so am left wondering if the elimination of marker use on the SP was coincident with the vacating of manned operator stations.

This is a point of curiosity I have about UP. UP adopted CTC almost system-wide proximate to WW II, and... I think... numbered trains except passenger trains were dropped from the timetables. "X-[engine #]" became practically permanent in changeable number boards. But did they run white markers or flags? Was there ever occasion to run green on a freight? Were flags used for anything other than fan excursions?

[nkalanaga]

If the train was an Extra, not listed in the timetable, it was required to have white flags or lights, at least through the 70s in the west.  Passenger trains very seldom ran as extras, unless it was a charter, fan trip, or a troop train, so they seldom had any reason for the white flags.

The early BN still ran some scheduled freight trains, so it would have been possible for them to run in two sections.  I doubt that they did, because it was easier to make the second section an extra.  That way the two didn't have to stay together.

The green flags/lights weren't for station operators.  It was for opposing trains, so that when they were at a meet, they wouldn't see the first section go by, think "There goes #97", and go on their way, right into 2nd 97.  A train could have as many sections as the dispatcher wanted to create, and all but the last one showed the green.  The last one didn't, so when it went by, the opposing train was free to leave, subject to any other rules or train orders holding it.

In my 1967 rule book, for the Northwest and Upper Midwest roads, the only use of green markers was to show that a train was in the clear, in a siding.  If the train still showed its red to the rear, overtaking trains were required to "travel at reduced speed", until they could see that the first train wasn't fouling the main.  There's nothing at all about what colors could be shown on marker lights to the side or front.  In the absence of a proper marker, a red light or flag could be substituted, with white used to show the train is in the clear.

[C855B]

Looking through old pictures, it appears UP discontinued enforcement of white markers around 1965. What's odd is I have a 1972 UP rule book stating that all extra trains are to display white markers on all locomotives. I guess there was a policy change circa '65 where nothing is an extra any more, so no markers are required. They had also used "X-###" in the number boards of extra trains, and this fell off about the same time, as well. I found a consistency in that locomotives delivered in and after 1965 had permanent number boards versus the earlier changeable style, so there we go.

SP's use of green markers for section(s) following lasted up through 1969 or '70, at least that's the last time I saw them. Hard to tell as a matter of policy, because the multi-section numbered freights I saw were in a unique period of heavy business, which then quickly dropped off to the point where they were annulling numbered trains from the schedule. (Another TT & TO feature, requiring the annulment of published schedules.)

UP was one of the roads adopting the green end marker on modern cabooses to signify siding clearance, as you mentioned. The rule book specifies the green marker is to only be used in "dark" territory. (It actually says "non-ABS", but in the rule book lexicon "ABS" is going to be any automatic signalling system.)

It just dawned on me that I have a friend who is a major employee timetable collector. I need to pose him my question in the form of when UP dropped numbered freights from timetables, and on what divisions. That will tell us when green (loco) markers or flags were an operating requirement.

[cv_acr]

Note there is some semantic confusion here from using the "marker" terminology in multiple ways...
"Markers" are specifically the indicators displayed on the rear end of the train.

The class lights or flags displayed on the front may also be referred to as "signals" in rule books and orders. ("Engine 201 display signals and run as First 97")

Use of green and white flags (by day) and/or lights (by day or night) would have both lasted to the end of using timetable for operation.

Use of rear end markers has no relation to the type of train or operation method.

[C855B]

Thank you, good point. "Classification Signals" in the UP rule books in the front, and "Markers" for the rear.

However, as mentioned, the 1972 UP rule book specifies use of a green marker light (or reflectorized flag) in non-ABS territory to indicate clearance when a following train is to pass. Otherwise, a red light (or flag) to the rear.

[nkalanaga]

Mike:  Yes, my rulebooks also say "non-ABS" for the green markers while in the siding.  With ABS, the trackside signals provide the protection.  I suspect that many crews continued to change the markers anyway, out of habit, especially if they also worked "non-ABS" lines, but it wouldn't have been required.

Chris:  I have also seen the class lights/flags referred to as "signals".  That can get confusing, because the railroads have a lot of different "signals"!  But you're right, the ones on the rear of the train are specifically "markers".  Today they're usually an EOT device, but it's still required to have a red light, flag, or reflector.

[cv_acr]

ABS isn't really a traffic control system though it's just a safety overlay.

Unless the ABS is part of CTC the signals don't convey movement authority they just relieve trains from doing their own rear end protection. Movement authority is still by timetable/train order or track warrants etc.

[seusscaboose]

Note there is some semantic confusion here from using the "marker" terminology in multiple ways...



Use of green and white flags (by day) and/or lights (by day or night) would have both lasted to the end of using timetable for operation.

THIS

[nkalanaga]

Chris:  Again, very true.  ABS will keep trains from running into each other, if properly followed, but trains still need other authority to leave the station(s).  In an "absolute/permissive" ABS system the siding exit signals perform part of that function, but the train still needs authority to be on the line at all.  NOTHING moves without timetable, train order, or (now) track warrant authority.  Even with CTC, it isn't a train until it has authority to leave the initial station.

[nkalanaga]

Question:  I wonder if any of the operations devotees, those who are sticklers for proper timetable and train order protocol on their railroads, use actual class flags or lights?  In the smaller scales flags, at least, would be out of scale, but no worse than objects on the top of cars for routing purposes.

[Missaberoad]

ABS isn't really a traffic control system though it's just a safety overlay.

Unless the ABS is part of CTC the signals don't convey movement authority they just relieve trains from doing their own rear end protection. Movement authority is still by timetable/train order or track warrants etc.

That was a big thing they hammered in at school, "abs is not authority". We still need a clearance to be on the main track.

Funny thing, they also told us it was an antiquated system and we likely would never see it in our careers.
And i go and work on one of the last (if not the last) subs in Canada to use it still

Personally I love Abs, item 6 protection is a pain the the a$$...

[cv_acr]

That was a big thing they hammered in at school, "abs is not authority". We still need a clearance to be on the main track.

Funny thing, they also told us it was an antiquated system and we likely would never see it in our careers.
And i go and work on one of the last (if not the last) subs in Canada to use it still

Personally I love Abs, item 6 protection is a pain the the a$$...

Maybe on CN, but CP has several subdivisions in southern Ontario at least that are ABS. (Windsor,Galt, Hamilton)

I recall an argument with another guy who was a CN engineer who commented on a photo of a friend's layout that his signals at a the end of the siding were wrong (they weren't) since he didn't understand the first thing about the arrangement when the signalling is only ABS not CTC.

[Missaberoad]

Maybe on CN, but CP has several subdivisions in southern Ontario at least that are ABS. (Windsor,Galt, Hamilton)

Good to hear there's still more out there 

I'm on CP (Leduc sub) which is the last ABS out west... considering almost the entire mainline was ABS at one point its still becoming pretty rare...