MMRS Signaling
The club has a fairly large main layout which is signaled in accordance with VR practice. The railway is HO scale (1:87) with a single-track main line running over six stations. There are also two branch lines.
The layout has about 78 interlocked colour light signals which are operated by the station masters. When the station master offers a train to the next station, the receiving station master sets the signals to allow the train to proceed. As the train travels, the signals are cancelled automatically. There is a four metre long signal repeater board on the back wall of the clubrooms which displays the aspect of all signals on the layout to assist the train drivers and station masters. Click here to see images of the repeater board.
Signals are interlocked with the points as a safety precaution. Interlocking prevents a signal being set unless there is a clear road for the train to travel, that is:
The points are not set for the track on which the train is standing,
On single line track (which is what we have at the club) if a signal is set for an opposing movement.
Changing the points will cancel a signal if it has been set.
The signals for the Club’s layout are all hand made from brass, castings and coloured LEDs. They are attached to the wiring with ex Telstra plugs and sockets which give very reliable contacts.
VR Signalling - a brief synopsis
VR signalling indicates to drivers not only whether they can proceed or not, but also at what speed they can go. The system is based on that used by the Pennsylvania Railroad in the USA. There are three speed ranges defined:
Normal speed is up to the maximum speed allowed on that track, or the maximum speed allowed for a particular train (for example, some rolling stock may be limited in the speed at which they can travel).
Medium speed indicates 40 km/h. This is used when a train is to negotiate a turnout or diverge from its current path.
Low speed indicates 15 km/h
Normal speed signals are:
Red over red – stop
Yellow over red – caution normal speed
Green over red – clear normal speed.
Medium speed signals are:
Red over yellow – caution medium speed
Red over green – clear medium speed
Yellow over green – reduce to medium speed.
Low speed signals are:
Red over red over yellow – caution low speed. This signal is used to “call on” a train into a siding, or a section of track which may be occupied. The train must stop at the red over red signal, and the signalman then lights the yellow lamp below the red signals to allow the train to enter the section. The club’s layout has one of these signals to permit locomotives to enter the turntable road.
On the MMRS layout, a train approaching a set of points at which it is to diverge will pass signals showing:
Green over Red, then
Yellow over Green, then
Red over Green, then
Red over Red if it is to stop, or Green over Red if it is to proceed.
If the train is to continue on without diverging, the same signals will all show Green over Red.
A fuller description of VR signaling can be found in Ian Weickhardt’s articles in The Australian Model Railway Magazine issues for August and December 2007.
