The Friends of the
National Railway Museum

South of England Group
Vice Presidents: Richard Hardy; Sir William McAlpine Bt, FRSE, FCIT, FRSA

Last Update

Talk Synopsis

16 April 2006

Signalling on the Great Cockcrow Railway
Tony Howker
10 April 2006

Twenty two members and guests were present as Tony began with a brief history of this 7" gauge miniature (not model) railway. Sir John Samuel started building before World War II but when he died it moved to the present site at Chertsey in 1968, when Ian Allan was persuaded to buy the infrastructure. There is nothing special about the land - it was an old piggery and poor-quality agricultural land, water-logged and next to the M25, so not much use for other purposes. Although privately owned, it is operated by volunteers and all the locomotives are owned by individuals. The layout has been enlarged and now covers 8 acres with a longest journey of 2 miles and takes 20 mins non-stop. It opens every Sunday from the beginning of May to the last Sunday in October,14:00-17:30, and runs 60+ trains, carrying 700+ people. Best attendances tend to be on those days which are damp in the morning and clear up in the afternoon - mum and dad then having to find something quickly to keep the kids amused. The site does not come under railway safety regulations as lines below 15" gauge are classified as entertainment; but since they have an ex- chief inspector of railways amongst the volunteers, there would be no problem even if they did.
Although trains can run with all the signalboxes switched out, then operating on "line-of-sight" principle like most other miniature railways, this takes away most of the fun. Signalling follows full professional practice. It is a complex railway with mixed semaphore and colour lights, and they take great pride in its operation. We looked at the contents and operation of each of the signal boxes. Cockrow Hill is a 16 lever mechanical frame, built around 1930 by the Railway Signal Co and came from Waterloo on the Waterloo & City line. The layout diagram was laid out to Southern Railway practice. Spring points are used to simplify operation were possible but others are motorised employing a Ford Escort wiper motor, through a spring loaded drive with detection off the motor, rather than the blades. It took 2 years to restore the frame in the workshop, but after this it took just 16 minutes to assemble it in the 'box. The block instruments are mainly LMS design - one being North British. The repeater signal indicators are included for show- strictly speaking they are not needed as most signals are visible from the 'box. The block bells are B.R. 1950s vintage but had never been used before installation at Cockcrow Hill. Full block book keeping is implemented using a genuine booking table with notice board. There is also a telephone switchboard. As elsewhere on the line, all semaphore signals, which are to the larger 10¼" gauge scale (as the equivalent 7" gauge ones look too small), are electrically worked and taken in at night to avoid attracting vandals. The plugs are MOD, gold plated and very reliable. Many are based on Great Central lower quadrant designs, the upper quadrant are LMS design. BR930 relays are used in relay room. There are heaters in all buildings to protect against damp in the winter when the railway is out of use. The track circuits are disconnected during winter to prevent electrolytic corrosion of the aluminium rails.
Everglades box is the most complex on the railway, and it normally needs two signalmen to operate. Block instruments are Southern pattern and the 31 lever frame was rescued from Croydon, together with the signalman's stool! A computer-based train describer is used to keep track of the trains - not an easy task as sometimes they run round the loops twice. The describer uses train identifiers which increment on each run, so it is easy to keep track of how many have been run during the day. The relay room at Everglades was the first one installed in 1971 and is rather cramped. The telephone exchange is a computer based one from Tesco!
Hardwick is the first box people see as it is at the main terminus station. The 23 lever frame is a Westinghouse "L" type, and the layout diagram is LMS pattern. Block instruments are Midland pattern and the bell is McKenzie and Holland from Australia. The semaphores are upper quadrant apart from the platform starters, with calling-on and warning/permissive arms, the latter to prevent stopping trains on the steep approach gradients which otherwise could risk stalling the train. Hardwick relay room is in a porta-cabin, although there is a plan to build a new station and relay room.
The final 'box is Lesters Crossing and has yet be fully commissioned. It came from Manchester Mayfield Station and was removed in 1960, although it is thought to originally be circa 1902. Currently the 'box just controls a crossing gate but ultimately it will be responsible for a bidirectional passing loop.
When railway moved in 1968 there were few trees but now the site is extensively covered - all self-seeded. In fact, they really need more to provide shadow and avoid the aluminium rails from buckling in the hot weather. Creosoted oak was originally used for sleepers but it was found that this lasted only about 10 years, and even this was only possible because no ballast was used to reduce wet rot. As the aluminium rail expands considerably more than steel, the lack of ballast resulted in substantial track movement. High density plastic sleepers are now used, which are immune from rot and so additional ballast can be added to stabilise the track. Expansion joints are also used, the overlap tapering over 2ft, but even so there is still track movement in the unshaded areas - hence the call for more trees. The rail lasts about 25 years and comes direct from the aluminium supplier using their own die. Typically they order 300ft about every 2 to 3 years.
There was an extensive question session, which Tony took in his stride. We learnt that locomotive boiler tests are made every year under agreement of the insurance company. These are done on site using their own test equipment with the insurance company providing the quality control. Many of the locomotives come from the heirs of owners who have died before completing the construction. A WD outline locomotive based on the railway is owned by the Science Museum, but was rebuilt at Cockcrow about 15 years ago. It is not a true scale model - there are some significant modifications, such as the valve gear position. While not an exhibit the Science Museum (or even NRM) would therefore want on display, it is a useful working engine for the line. They turned down an offer from the NRM to provide a South African model because it is foreign, too big for the turntables, a model of a narrow-gauge outline, and an oil burner - all of which make it unsuitable for the line.
Finally, we learnt that the training to be an engine driver on the line is as stringent as to be a signalman. This includes examination both on rules and routes, together with a period of several operating seasons to gain experience. Even so, there are still occasional SPADs,, all of which are investigated by an internal inquiry board.
The South of England Group benefitted from a special Sunday morning visit in 1997 (see visit report), but commercial organisations can hired the railway for private functions on summer Saturday for a cost of about £1000.

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