Hello everyone,
I am looking for some information on how US railroads implement shunting (switching?) controls. On Russian railroads dwarf shunting signals with two lights are used on sidings, while normal height light signals are used on the mainline (and on sidings, too) to control regular train movement.
I read an article on this site about control systems adopted in the US, but it does not deal with shunting. How does the train crew know that it's safe to do switching?
Thanks.
paulney wrote: Hello everyone, I am looking for some information on how US railroads implement shunting (switching?) controls. On Russian railroads dwarf shunting signals with two lights are used on sidings, while normal height light signals are used on the mainline (and on sidings, too) to control regular train movement. I read an article on this site about control systems adopted in the US, but it does not deal with shunting. How does the train crew know that it's safe to do switching? Thanks.
Hi and welcome aboard Paulney,
Switching is mostly done in yards, and here our yards (themselves) are unsignaled. The tracks in the yard are under the "yard limits" rule where all movements are at restricted speed. At restricted speed all trains must operate ready to stop short of any trains, equiptment or men fouling the track. If there is more then one train switching the yard then crews will usually keep in touch with eachother if necessary to avoid conflicting moves (this may also be done through someone in charge of the yard).
If nessasary, a train working in the yard can go out on the main, with the dispatchers permission, and in this case a signal may be encountered if the traffic controll on the main is with a signals (as in CTC, Centeralized Traffic Controll). Thats not always the case.
In dark territory (and for switching in signaled territory) the dispatcher will give the train a track warrant for "work and time" within designated limits. The switcher can not excede these limits. These limits may be "joint" limits with other trains, equiptment or men. In the case of "joint" time all trains will operate at restricted speed. If the main was signaled (CTC or ABS) the signals protecting the section(s) of track would show red, but the trains will operate within their authority under restricted speed anyway. This would apply to a switcher switching a spur or branch off the mainline as well if were nessasary to fowl the main.
So, basicly we don't switch by signal indication. We do use signals to enter the main from the yards and exit the main into the yards on signaled mainlines though. Someone here might correct me on this as there always seems to be exceptions to the rule in railroading somewhere.
Oh, one more thing, we do have some yards that have small signals to indicate switch position (like the BNSF Barstow yard) but these signals DO NOT give the train any kind of authority, thay just make it easy for the crew to see the switch position (which may be capable of being controlled remotely).
If you are asking about the signal systems themselves that govern movement, well one can (and has) written books on all the different systems, signal types and aspects we use in this country. Most of the signal systems were installed by the class ones back when there were many many companys, and each usually did thing there own way makeing for endless variations in the methods used.
Hope that answers your question Paulney.
Wow! Thanks a lot for such a detailed answer. I was suspecting something like that - that a typical switching operation in US is not done anywhere in the vicinity of a platform/station, but rather in designated areas only. I've never seen a switching loco and rolling stock consists shuffled around anywhere around passenger stations (something quite typical for a railroad in Russia).
Is that something of a historical legacy where each competing railroad would have its own switchyard for operations, as opposed to a consolidated government-controlled railroad that did not have to worry about using competitor's tracks?
The reason I was asking - I am currently doing my first layout, and then it occured to me that I've never seen a dwarf signal around here. They actually look very neat at night - a sea of white and blue lights scattered around and reflecting in the steel rails.
paulney wrote: Wow! Thanks a lot for such a detailed answer.
Wow! Thanks a lot for such a detailed answer.
Yes, well done Chad.
Paulney, there are 17 pages of pictures of dwarfs on this site-http://www.rrpicturearchives.net/srchThumbs.aspx?srch=dwarf&search=Search
Paulney:
What you're seeing is a sharp difference in practice between European-style railroading and North American-style railroading. In European practice, all turnouts are within "stations", a location with side tracks that may include yards and are under the control of a stationmaster, are frequently equipped with remote-control turnouts and signaling to direct movements, and a local interlocking plant is used. No one on a train gets on the ground to throw switches by hand; that job if not done remotely by a train director is handled by switch tenders. The stationmaster has absolute power over his terminal and directs all train movements. In North American practice the local interlocking plant in a station is almost unheard of, except in passenger terminals but almost always limited there to the platform tracks and throat and not extending deep into the servicing areas. North American railways tended to push authority to a lower level, and trains direct themselves inside stations. Moreover, North American railways had no compunction against putting turnouts anywere it was convenient, and many turnouts are not anywhere near a "station" by European definitions.
Remote-control turnouts are rapidly coming into vogue in North America in yards and industrial plants, but are generally radio-remote and are operated by each train crew and not by a central location. Centrally-controlled turnouts are generally limited to the throat in hump yards and other key but compact locations.
I have spent quite a bit of time working with developing-world railways, and in the ones that emulate European practice you cannot get an engine driver to get off his locomotive to operate a turnout. It crosses craft and cultural lines and they look at you with horror and disbelief. In North America the train crew would conversely be astonished and appalled if you told them that from now on they could make no move except as directed by a yardmaster, and productivity would go to zero pretty quickly.
Each system has advantages and disadvantages. For dense, short-train, tightly-scheduled, European railways their system makes a lot of sense. For intermittant, long-train, flexible North American railways its system makes a lot of sense. Developing world railways in the cases where operations are not dense are changing toward North American style where it is culturally feasible, in order to lower costs and compete with trucking.
RWM
paulney wrote:Is that something of a historical legacy where each competing railroad would have its own switchyard for operations, as opposed to a consolidated government-controlled railroad that did not have to worry about using competitor's tracks?
Not only historical legacy but still the practice today. There are many "joint" yards, however, both historically and at present, shared by two or more railways for the benefit of both. In large cities there are often "belt" or "terminal" railways owned by two or more of the railways serving that city that operate classification yards for the benefit of their owning railways as well as tenant railways.
For example in Denver, Colorado, in 1980, there were the following yards: