I’m new to the group and the hobby. Just in the layout planning and general learning stage. Haven’t had much chance to observe prototypical switches and signals. would like to learn about them. I’m sure signals vary from railroad to railroad or region to region.
I’d like to get a basic explaination of what signal light groupings and light colors are used in any given trackage arrangement. Links to pages with detailed explanations and pictures or drawings would be much appreciated. Actually, so would any info on the topic. I’m sure once there are some answers posted, I’ll have more directed questions. Thanks in advance to all who can provide some info or insight. Dave J.
There is a truly ancient softcover book, All About Signals by John Armstrong, which at least one Class 1 railroad used as an instruction manual. The material originally appeared in Trains magazine in June and July 1957. This is my ‘go to’ source for signalling information.
There are also several pages of signal aspect diagrams in Peter Josserand’s Rights of Trains, THE book for everything pertaining to rules during the transition era and before.
The third source is more, “Up close and personal.” Try to meet some of the folks who maintain and use signals. If you can meet some railroad employees, retired and otherwise, they are gold mines of signal lore.
Since every railroad had its own standards, some of which were truly unique, you will have to choose a prototype and try to learn all there is to know about that line - or go freelance and set your own consistent standards.
Here are some basics for US signalling. This information comes from NORAC Operating Rules, 8th Edition, effective, 1 January 2003. First some definitions. My comments are in italics:
Block: A length of track with defined limits on which train movements are governed by block signals, cab signals, or Form D.
Control Station: The Dispatcher’s office or the location where is Operator is on duty, from which remote control signal appliances or switches are operated.
Controlled Point: A station designated in the Timetable where the signals are remotely controlled from the Control Station. This is usually, but not always an interlocking.
Controlled Siding: A circuited siding in which both ends are controlled and governed by signals under the control of the Dispatcher or Operator. Controlled sidings are equipped with power switches.
Non Controlled Siding: A non-signalled siding. Entrance into or out of the siding is controlled by the dispatcher, but movement within siding is made at Restricted Speed at the discretion of the train crew. Non controlled sidings may have powered or hand operated switches.
Industrial Track: A track other then Main, Siding, or Yard Track, upon which movements must be made at restricted speed.
Interlocking: An interconnection of signals and signal appliances such that their movements must succeed each other in a predetermined sequence, assuring that signals cannot be displayed simultaneously on conflicting routes. The tracks between opposing Home Signals of an interlocking are referred to as Interlocking Limits.
Main Track: A track designated by Timetable upon which train movements are authorized by ABS, CSS, DCS
Nick covered a wide range of topics, just be aware that some of the terms may be different in other rule books and eras.
For example instead of “Form D”, the western half of the country uses Track Warrants and Track Bulletins.
CTC is called TCS on some roads. ABS is also known as APB (there are differences which the signal experts can expound on, but in rule books they are used almost interchangeably).
Cab signals come in several varieties. ATS - Automatic train stop, ACS -Automatic cab signals, CCS - coded cab signals, etc.
Depending on era timetable, train order or DTC (direct traffic control) were also used as main track authoirites. In CTC, track and time and verbal authority can be used on the main track.
Rule 251 is also called “double track” or “current of traffic” and in the modern General Code of Operating Rules (almost everything west of the Mississippi since 1985) its rule 9.14 instead of 251.
First off, thank you to those who have already replied to my first post about signals.
I need to better clarify what it is I want to know. My expreience with signals has primarily been seeing a few on Canadian ( CN & CP ) tracks, but have not had much chance to observe them when trains are near. I’ve also seen some on various HO layouts, but do not know if they are “operating” properly, or if they are mostly just lit up for decoration.
What I’d like to know is how many signal lights are used in a given location and in what color combinations.
Example # 1 - a train waits on a siding to right of the mainline, near the turnout that will bring the train back onto the mainline. Is there just one signal post ahead to the right, or one to the right of the siding and one to the left of the main in this case ? How many lights on each post ? If two posts and one signal per post, I assume the one to the right of the siding would show red to stop the train and the one to the left of the main would show green if another train were overtaking and red if another train were oncoming/passing. In this case, when the sided train is clear to proceed, would the signal to the left of the mainline show red, to stop overtaking trains while the sided train moves ont the main ?
Example # 2 - Same senario as above, but with double track main, plus a siding to the right of the righthand main. How many posts, positioned where and how many lights ?
Example # 3 - One mainline and one siding to the right. Train on mainline, approaching siding. Are there any signals on the mainline, before the train reaches the siding ? I assume so, to tell the train to proceed, or “pull over” onto the siding. If so, what color scheme to signal proceed on main and what color scheme to signal pull onto siding ?
Example # 4 - I THINK I’ve seen a singl post with 3 lights, mounted one above the other. How w
ABS you would have signals beyond the points of the switch on the single
track, with a head in each direction. The head for trains coming towards
the station/siding would have one or two heads. The signal for trains
leaving the station/siding would have one head. In ABS single track the
signals don’t convey authority, just condition and occupancy. Only one of
the signals can be anything other than all red or all dark.
CTC you would have 3 signals at the switch, one on each route into the
switch. There would be a single head signal on the main and the siding
for trains leaving the station/siding and a two headed signal beyond the
points on the single track for trains coming towards the station/siding.
Once again only one of the signals can be anything other than all red or
all dark.
Same as above only all the signals on the “righthand main”, no signals on
the lefthand main.