Signal staff tokens.

[Wexford70]

Hi guys, 

I am looking for some detailed explanations as to how the signal staffs for single lines were used and for information of the different types used by the early railways and then by CIE.

Did the position of the rings play a meaningful part in their use?

Would anyone be able to point to some useful resources?

With thanks

Edited February 13, 2021 by Wexford70

[Galteemore]

http://www.trainweb.org/railwest/gen/signal/sl-intro.html

See also here:,https://www.bluebell-railway.com/brps/signalling-staffs/

The rings are indeed significant. They reflect the ‘configuration’ of the staff to ensure that the crew of a train have the right staff for the section - especially significant where a line was made up of numerous consecutive single line sections. Often trains were worked by ‘staff and ticket’ and the crew might only see the staff and be given a ticket. It would be  easy for staffs to get mixed up without a means of differentiating them, which is what the rings do - as well as their mechanical function in the instrument, explained well by Dhu Varren below.

The crew can easily see if they have or are being shown the correct staff for the section they are entering and haven’t just been given back the staff for the section they have just left ! 

Assuming, of course, that they bother checking. At Abermule in 1921 they didn’t: ..https://en.m.wikipedia.org/wiki/Abermule_train_collision (it was a tablet rather than staff in this instance but you get the idea).

This is how the SLNC differentiated them...

 

Edited February 13, 2021 by Galteemore

[Dhu Varren]

The arrangement of the rings on a train staff were different for every section of track. They acted like a key to ensure they could only be inserted back into a machine appropriate to the section of line to which the staff was applicable. For the train crew, identification of the section of line to which the staff was applicable was simply by the name of the section being stamped, or cast, on the staff, ie station A to station B. The signal box at each end of the section was equipped with a "token instrument".  This was a machine which detected the removal or replacement of a "staff" or "token".  The token was a metal key which was smaller than a staff but which performed the same function.  The token instruments at each end of a single line section were electrically interlocked so that the act of removing a token/staff locked both machines and prevented further removals from either instrument until the missing token was replaced at one end or the other.

Headhunters Museum in Enniskillen have a fine collection of train staffs, one for every line section for the GNR (INWR) line from Enniskillen to Derry.

[minister_for_hardship]

Staffs, both large and miniature electric types and manual (one engine in steam) staffs were used widely in Ireland.

NCC and Tralee and Dingle preferred tablets. Some GNR lines also had tablets.

Cavan and Leitrim used Wise's Patent staffs. The Croom branch had an unusual divisible staff.

There were also key token and ball token systems, neither of which used here as far as I know.

Edit: NCC had some key token working it seems, the County Down was another tablet user.

Edited February 15, 2021 by minister_for_hardship

[Galteemore]

Interesting subject. Speedy tablet exchange on the NCC main line to Derry was critical to the tight timetabling that this LMS component prided itself on. 60mph exchanges using tablet catchers were quite common - eyewitnesses of the operation in diesel days testify how noisy it could be at close hand! The LMS Society have some great stuff on this.http://lmssociety.org.uk/topics/singleLineWorking2.php

In Northern Ireland, the LMS's Northern Counties Committee adopted the Manson system for much of its single track lines and equipped a high proportion of its front line locomotives with the catcher or 'snatcher' as it was known over there. Photographs indicate that most, if not all, of the following NCC classes of locomotive were fitted on the left hand side with the Manson style of tablet exchange equipment: 2-6-0s: W Nos. 90-93 (all); 4-4-0s: A, B, B2, B3, D, U, U1, U2 (all); and 2-4-0s: G, No. 40's being on the tender. Even J class 2-4-0ST Nos. 25 and 47 were equipped with the arm on the diminutive bunkers sides. 

The 2-6-4T WT class, colloquially known as 'The Jeeps', were a special case. The first example No. 5 was fitted with the apparatus on both sides in the conventional position below the rear cab window, but due to the considerable width of the cab, the arm was rather short and hence the head very low down. This meant the fireman had to lean out of the door and reach down to a similar level thereby exposing himself to some risk of danger. As a consequence, subsequent engines had the apparatus fitted to the cab door, and No. 5 in time likewise modified. 

Generally, to eliminate further risk of misalignment as a locomotive negotiated a curve with super-elevation, it was found desirable to locate ground tablet apparatus exchange posts on straight lengths of track. Ground apparatus was unlikely to be provided at terminal stations, due to the train being stationary prior to departure, or due to stop upon arrival, the token could easily be passed over by hand either at the platform or as the locomotive slowly passed the signal box. It was also permitted to throw off the tablet as the train passed a signal box at certain locations, including on the NCC: Larne (non-stop trains composed of corridor stock); Larne Harbour; Cookstown Jct; Macfin (non-stop Down Derry Central trains); Coleraine Jct (trains running tender first from Portrush, also trains from Portrush and Derry line at the Down platform); Portrush; and Derry (passenger trains only).

Edited February 15, 2021 by Galteemore