Cork-Cobh Re-signalling

OLIVER DOYLE

The Cork-Cobh section was re-signalled on Easter weekend starting on Thursday 1 April 2010, when the signal cabins at Cobh and Glounthaune closed permanently at 20:17 and 20:25 respectively. The system was commissioned at 21:37 on Monday 5 April. Apart from the Waterford West-Waterford Central section, the Cork-Cobh line was the last line in Ireland to be worked on the Double Line Absolute Block system using the age-old Harpers Block instruments. These were manufactured in London by W. R. Sykes/Interlocking Signal Co. Ltd.

The Cobh end of Cork station is mechanically signalled using levers 73-110 of the old 110-lever frame. From 1975, the opening year of North Esk Freight Terminal, the block posts were Cork - Little Island - Cobh Junction - Cobh. With the demise of the Youghal branch, Cobh Junction was normally switched out as the 30-minute frequency on the Cork-Cobh section at peak time could be accommodated with a long section Little Island-Cobh. This was the normal working until the re-construction of the Midleton branch 2008-9.

The up & down protecting signals for Myrtlehill level crossing are the Cork up outer home (CK109) and down advance starter (CK78) signals, because of the proximity of the gates to the station. These signals were converted from mechanical semaphore type to colour-light type during the re-signalling. The ground frame at Myrtlehill was decommissioned. On 28 July 2009, the level crossing was converted to a 4-barrier CCTV type worked locally by the crossing keepers and on 16 April it became remotely monitored from Mallow Level Crossing Control Centre. During the Cobh Line platform re-construction programme 13 October to 21 November 2008, North Esk sidings were disconnected and the signal cabin at Little Island, with its electric panel, was closed. Glounthaune was then switched in most of the time to facilitate the re-construction of the Midleton branch and then for its operation (See JOURNAL 170). The lever frame at Glounthaune had 20 levers and was manufactured by the Railway Signal Co. After the rationalisation of Cobh station in 1959, it was worked by a Railway Signal Company 30-lever frame supplied originally to the Great Northern Railway (Ireland) and recovered from Monaghan South. A feature of the frame, unique on IÉ, were the sprung catch blocks with exposed springs – these were usually gravity worked. The 2-lever ground frame which controlled the locomotive release at the buffer stop end of the station was removed as part of the re-signalling during the last week of March.

The re-signalling of the Cobh line was always planned to be accommodated on the Cork East (prefix CE) signalperson’s console, a Personal Computer based system, located in Glounthaune signal cabin, which initially controlled the Midleton Line. This, in line with the other IÉ CTC systems installed in the last 10 years, is a Solid State Interlocking (SSI) – the actual SSI being located in Cork. At the commissioning of the Cobh Line signalling on 5 April, the console was moved from Glounthaune to Cork signal cabin but retained a separate signal person. As is now standard on IÉ, train detection is by axle counters.

Between Myrtlehill and Glounthaune, there are two sets (caution & stop) of intermediate block signals. At Glounthaune, the double junction layout is in line with that at other double junctions where space permits. There is a trailing crossover between the up and down lines beyond the Cobh end of platforms and then a turnout for the up Midleton line. This layout provides a crossover for single line working during engineering work or obstruction between Cork-Glounthaune and Glounthaune-Cobh. The East Cork network is designed for a 15-minute service on both the Cobh and Midleton sections. A loop is provided at Glounthaune on the Midleton line allowing up and down trains to cross clear of the Cobh Line and also provide a run around facility for permanent way trains. No such facilities are provided at either Cobh or Midleton as the cost could not be justified and in the event of a Permanent Way train requiring to operate, a second locomotive will be used to haul back the train.

Between Glounthaune and Cobh there is one set of intermediate signals thereby giving five sections between Myrtlehill and Cobh. At the latter the line terminates at the single platform, while there is a short siding on the up side. The trap points on this siding and that at Midleton have a flashing reminder for the signalperson when they are not in the trap position but are free to be moved to the trap position. This is the first use of this arrangement on IÉ.

Following completion of this project there are only 13 mechanical signal cabins remaining in regular use on IÉ; Cork, Navan, Limerick Check, Limerick Junction North, Limerick Junction South, Tipperary, Clonmel, Carrick-on-Suir, Waterford West, Waterford Central, Wellington Bridge, Birdhill & Roscrea. Church Road, Dublin, is designated a ‘shunting frame’.

The remainder of this article appears in IRRS Journal number 172, published June 2010.