It is a common belief amongst the heritage railway community that having a main line connection is good for business. This not only facilitates stock movements in and out but, with the right signalling off the main line, charter trains can visit the line and bring commercial benefits.
The Severn Valley Railway (SVR) has long had such a connection but this was via a trailing connection not fitted with facing point locks making movements a somewhat tortuous affair. All that has now changed, but the circumstances are interesting.
Kidderminster, the junction for the Severn Valley Railway, had a traditional mechanical signal box on the line from Birmingham to Worcester. A trailing crossover between the up and down line, allowed terminating trains to reverse there. The signal box operated the points and the associated shunt signals for the Severn Valley Railway connection.
In August 2012, the main line was re- signalled and came under the control of the West Midlands Signalling Centre (WMSC) located at Saltley. This project incorporated the provision of a new facing crossover on the main line to make the reversal of terminating trains easier. It was quickly realised that this would create a facing movement over the points leading on to the Severn Valley Railway meaning that they would need to be equipped with a facing point lock.
Why therefore not make this a fully signalled route thus facilitating quick and easy movement on to and off the heritage line? Negotiations with Network Rail commenced with mutual benefits being realised by both parties and a collaborative design was prepared.
Design and Implementation
The Severn Valley Railway had constructed a GWR replica signal box at Kidderminster in 1987 to control the station throat and associated sidings as well as the line towards Bewdley. This box now became a fringe box to the WMSC. The connecting line also serves as access to the SVR Carriage Works, a facility created from the old Goods Shed.
The SVR is entirely equipped with mechanical semaphore or shunt signals, but clearly a signalled main line connection would need to be colour lights to the latest standard, protected by full track circuiting. So who should control the points and signals?
The solution was a joint participation. A release from Kidderminster SVR Box allows the WMSC to operate both ends of the point connection and slots allow it to clear the appropriate signal from either the Up or Down platform on the main line onto the SVR. Depending on which levers are pulled in Kidderminster box, this can either be a main line aspect that clears the route towards Bewdley or a position light that allows movement only within station limits.
The section from Kidderminster to Bewdley is controlled by acceptance levers instead of the more usual token instruments that exist on the rest of the railway’s single line sections, so having to stop to pick up a token is avoided.
The departure signal from the SVR is an LED colour light where the main aspect is controlled by WMSC once the points are reversed. On the same post is a position light signal worked from a lever in Kidderminster Box that controls entry to the carriage works. To save using another lever for controlling the exit from these sidings, the mechanical disc exit signal is wired in parallel with this, both thus showing clear aspects at the same time.
An unusual feature is the protection for trains coming out of the carriage workshop. Space constraints prevent the use of trap points so each of the three exit tracks are equipped with motor operated derailers. These are normally ‘swung-up’ over the rail head and ‘swing down’ for movements to enter or exit the carriage works.
A 37-core cable connects the SVR to a Network Rail lineside cabinet for transfer of control and indication circuits between the two railways. These in turn connect via data links over the FTN telecoms network to the Solid State Interlocking at the WMSC. A direct telephone link enables the signallers to communicate when any train movements are scheduled.
The SVR is a line that has a fine heritage of preserving for posterity mechanical and relay technology. With its new main line connection, it now has signalling that spans 180 years of development. May the connection bring it new commercial opportunities as well.