SECTIONAL APPENDIX - HALWILL
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General                                     
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Halwill, sometimes referred to as Halwill Junction, was opened by the L&SWR in 1879 as a station on the line from Okehampton to Holsworthy. This line branched off the L&SWR main line to Plymouth at Meldon Junction.
Halwill became a junction with the opening of the North Cornwall branch to Launceston in 1886. This line was extended in bits and pieces, reaching Wadebridge in 1898 and its final destination Padstow in 1899.
The line to Holsworthy was extended to Bude in 1898.
The branch to Torrington was a late addition, build by the SR in 1925 under the 'Light Railways Act'.

With 4 single lines joining into one junction, Halwill was the largest junction of just single lines in Britain. But it was by no means a very busy place.

Traffic on the 'main line' was about 5 or 6 passenger trains per day between Okehampton and Padstow. Most of these trains had a portion to or from Bude. One of these trains was the famous "Atlantic Coast Express" direct to or from Waterloo, but by the time this reached Halwill it was little different from the normal local trains.
There were some additional local services between Okehampton and Bude (including school trains), and an early morning / late evening service from and to Launceston. Freight traffic was light with just a few trains per day.

Traffic on the Torrington branch was very light, with just 2 passenger trains per day, consisting of just one coach and probably carrying also just as many passengers. These trains were officially classified as mixed trains. There was also one daily freight service on the branch in both directions.

The Torrington branch closed in 1965 and the other lines followed shortly after in 1966. Halwill Junction is now little more than a distant memory.

Signalling
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The layout as presented in this simulation represents the situation from around 1945 to the closures which started in 1965. The last major addition was the contruction of the Up Siding in 1943.
Information was taken from G.A. Pryer's book "Signal Box Diagrams", volume 13.

The main frame was a 43 lever frame, to which 2 levers (C and D) were added for the Up Siding in 1943. Two other levers, A and B, operated the level crossing gates lock and wickets. The level crossing gates were operated by hand.
Part of the layout was worked through ground frames as detailed below.

Adjacent boxes are :
Ashbury (Up & Down Main, towards Okehampton)
Ashwater (Up & Down North Cornwall, towards Launceston - Wadebridge - Padstow)
Dunland Cross (Up & Down Bude, towards Bude)
Hole (Up & Down North Devon & Cornwall, towards Torrington)

The single lines were worked by Tablet except for the line to Ashbury which was worked by Electric Key Token.

Three ground frames controlled part of the layout.

Groundframe A controlled access to and from the Middle siding, as well as the cross-over to the ND&C. Two levers, 37 and 38, were used to release the FPL's controlled from the groundframe, A1, A2 and A8. When these were unlocked, the switches were released. The FPL's were special in that they only locked the switches in normal position, these FPL's remained unlocked when the switches were placed in reverse position. When the switches A3 and A4 are placed in reverse position, signals 36 and 39 are slotted by the groundframe levers A6 and A7. Lever A6 also slots signal 23. FPL A8 required lever 38 reversed to be released, but it also required the Torrington line tablet.

Groundframe B controlled the points which gave access to the ND&C loop. There were no signals to control movements in this area. Groundframe B was released by the Torrington line tablet.

Groundframe C controlled a cross-over between the Up Sidings and the U&D Main on the far side of the Up Sidings, towards Ashbury, just beyond signal 2. This frame was released by the Key Token for the Ashbury line. There were no signals controlling this cross-over. This cross-over has not been included in the layout, see below for more information.

Adaptations
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Some adaptations were required in order to work with PC-Rail.

Signal E.
Signal E is added on the Down platform, in order to allow shunt moves into the Down platform from signals 26 and 34 and also to control shunt moves from the Down platform to the U&D main and set-back moves from the Down platform into the Up sidings. In reality, this signal was worked by lever 25 with switch 11 selecting which signal was cleared when 25 was reversed (signal 25 or E).

Groundframe A.
The program cannot handle the slotting of a signal for a particular route only. Instead, reversing levers A6 or A7 is set as condition for clearing signals 23, 36 or 39 as applicable, see locking table for details.

Groundframe B and signals on the ND&C line to Torrington.
Two shunt locations have been set up in the loop area on the ND&C to allow proper control of shunt moves in this area.
Shunt location DCL controls the exit from the ND&C loop in the down direction.
Shunt location DCM allows trains to reverse after clearing switch B2. Note that it is not necessary to clear this shunt location for trains coming from Hole with signal 41 cleared.
Note these shunt locations cannot be operated when a train has been accepted from Hole. Also note that signal 41 can only be cleared if B1 and B2 are in normal position. Lifting FPL A8 will also lock signals 40 and 41. Freight trains coming from Hole must therefor be stopped at signal 42 before the route can be set to the applicable siding.
Furthermore, the section of the ND&C line between switches B1 and B2 has been allocated to a separate location (ND&C line) in order to be able to properly define shunt moves from the station to this section and back. Please note that any unbooked trains (with *Z** headcodes) passing this section will stop in this location, and the 'proceed' command must be used to restart the trains.
Signal 40A is added in order to comply with the program rule that there must be a single exit signal, and also to allow shunt moves in the ND&C loop area.

Groundframe C.
The crossover controlled by groundframe C has not been included. To include this would have required a large number of additional signals and points, e.g. access points to the other tracks in the Up Sidings, new Section, Home and Starter signals (the crossover is beyond signals 2 and 24), exit signal from the sidings and access signals from the spur into the sidings.

Level crossing.
Lever A is used to operated and lock the gates. The wickets are not included and so lever B has been left out.

Local Instructions
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Trains booked to stop at Halwill station are exempt from the requirements of Rule 39(a), i.e. signals may be cleared for trains stopping at the Station without the need for trains to be brought quite or nearly to a stand at each signal. See also the information in the locking details.

Platform Lines and Sidings
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Permissive working is permitted on both platform lines, for both bays, Middle siding as well as the ND&C and ND&C loop between sigs. 40 and B5.

Platform lengths (1 unit equals 1 engine, 1 coach or 3 freight wagons):
Up Platform   : 6 units (longer trains allowed into the platform)
Down Platform : 7 units (longer trains allowed into the platform)
Bay Platform  : 5 units
ND&C Platform : 4 units
Middle Siding : 22 units
ND&C Loop (also ND&C line between B1 and B2) : 7 units

Note that freight trains can be timed to stop in the Up platform or Down platform, but can not terminate there.
Freight trains can also not terminate in the Bay platform or the ND&C platform.

Train Reporting Numbers
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Train reporting numbers only came into use in later years, and also changed over the years. See timetable information for details.

Speed Restrictions
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Overall : 40 mph
Station Area (approx. between points 11 and 16) : 25 mph
All bay platforms, siding leads, middle siding, ND&C loop : 15 mph

Acknowledgements
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First and foremost thanks to John Dennis for his extensive work on changing the program such that it became possible to build this simulation using just data definitions.
Also thanks to all on the pcrtest-team for their help in testing this simulation, in particular Peter Dean for helping with some locking details, and Alan Ashley for helping with the engine diagrams.

The opening picture was kindly provided by Alan Duckworth. It shows Halwill station from the west in 1965, the appropriate caption reads "not long to go ...". 
