Swanley New Barn Railway
Volunteers
The railway is run by the Swanley New Barn Society, with everyone you see on your day out at the railway a volunteer.
The railway accepts volunteers from the ages of 16 upwards.
All training for driving, guarding, signalling and other activities is given on-site by experieced members. We are actively seeking people over the age of 18 who would like to drive and or signal on the SNBR. With a minimum of 3 days driving and a few days help in the winter months is all we ask for. Most of our Adult members pass out for driving diesels and signalling, while steam engine driving takes a little longer to learn.
If you would like to join please contact us via Facebook
Signal Box - Holborn Crossing
During the first year of operation of the railway a signal box was built at Lakeside station (subsequently renamed New Barn station) to control the signals and points in the vicinity of the station. Track circuits and point detection is installed throughout the layout enabling the signal frame to be fully interlocked. The layout has been changed several times during the railways existence and in its present form the box controls 7 sets of points together with 17 signals.
Signal frame
The signal frame is one of the few Westinghouse Type L still in operation. The 35 lever frame was originally part of the Gloucester Road (Croydon) signal box installation.
The levers are fully interlocked with the signal levers, point detection and track circuits.
While the look and feel of the original has been retained, the locking logic is accomplished electronically using a PIC micro controller rather than using the D-bands and linked relays as in the original.
The use of software to control the box simplified making the modifications needed to track the changes that have occurred to the layout through out the history of the railway.
It also enables an automatic mode to be included enabling the railway to be operated in the absence of a signalman.
For the first 15 years of its life, multiple small boards were used for the interface to the levers, track circuits and point detection switches. The connectors used on these cards became increasing unreliable, so in 2002 the system was updated to use a single custom PCB to handle the connections to all of the input signals.
The original output cards containing the driver interfaces for the interlock solenoids, signals, diagram and point motor relays are still in use but with the connectors replaced with high reliability ones.
Points
These were originally operated by windscreen wiper motors modified to have two stop positions, they have now been replaced by linear actuators giving a significant improvement in reliability.
Sealed micro switches are used to detect the position of the point blades, which is fed back to the signal frame to verify that the points are positioned correctly before a signalled route can be set up.
To allow some limited operation to be maintained in the case of a mains supply failure, the points system operates from a constantly charged 12v battery.
Signals
The layout is fully signalled with colour light signals. These were originally constructed using commercial vehicle marker lights running on 12v AC, switched by triacs. They are being gradually being moderised using LED’s. The reduced power requirement of LED’s means that a signal at Parkway station, ¼ mile away is now practical.
The approach signal to New Barn incorporates a numeric seven segment display to indicate the destination platform to drivers
Track circuits
Track circuits are installed through out which drive the display in the signal box. In the station area these lock the points, while in the more remote sections of the layout they are used to indicate the position of trains. As the railway is in an open public park the wiring and other circuitry has to be hidden underground which results in a continual battle against the effects of damp and corrosion.
PA systems
Most recently P.A. systems have been installed at both stations to broadcast passenger information. The one at New Barn is a fully fledged one driven from a touchscreen interface in the signal box. The one at Parkway is more limited, broadcasting safety information being triggered automatically by the track circuit system.
The SNBR signal box is named Holborn crossing in memory of our founding member and original driving force of the railway, Christopher Johnson. Chris during his BR career was at one point an area manager with Holborn Viaduct being part of his patch. This now closed station was for a period a 3 platform terminus similar to New Barn station. However we don’t have a viaduct, but we do have a crossing hence the name Holborn Crossing was chosen as a subtle but fitting way of remembering our beloved Chris. In 2016 a commemorative plaque was unveiled on the side of the signal box by Chris’s family led by his widow Sally
History
The Swanley Narrow Gauge railway openned as a private venture in 1986. This ran over half the present route, using 1 engine in a push pull system. The initial operators had massive plans, including to build a big boy steam engine. The original track design also included a 30' turntable to be located between the signal box and the carriage shed. funds and other better ideas, like putting the turn table at the end of the station meant this turn table was never built. The big boy plan never proceeded either.
In 1987 the railway came under council control and was renamed Swanley New Barn Railway (the park was then called New Barn Park). By the end of 1987 the railway was changing control into the present operators the Swanley New Barn Railway Society after the then council were considering closing the railway due to the costs of operating the railway with paid staff.
In 1987 the railway was completed as a circuit with a 3 platform terminus one end and a Halt the other (adjacent to the main car park). The railway has improved every subsequent year to point that the early pioneers may well forget how far the railway and society have come along. With one of the largest engine and carriage fleets in 7 1/4" gauge and more on the way.