Our Guildford Branch team member and Network Rail Signalling designer, Simon Paley, takes a look at the 3rd and 4th Rail electrification systems. In this final part in the series he discusses the conductor rail accessories and other relevant lineside details. Check out Part 1 - 3rd & 4th Rail Systems - Part 1 - The Background and Design here and also Part 2 - 3rd & 4th Rail Systems - Part 2 - Modelling Guide here.
Conductor Rail Accessories
There are some key details that third rail modellers can also add to their layout to help them bring it to life.
For modellers that model any period after the 1950s, then AWS magnets are definitely needed, and those on the Southern Region were Green, to denote that they were extra strength.
The other key component is the Impedance Bond, these are pieces of equipment mounted between the rails to allow track circuits to function and the return electrical current to run through the running rails. There are two common types of bond, the BR Type 3 (for most track circuits) and the BS3000 bond (for use with TI-21 Audio Frequency Track Circuits).
For more information on both AWS Magnets and Impedance Bonds, see my book - Colour Light Signalling for Model Railways.
For post privatisation modellers, there’s one final detail which you can add. Recently, Network Rail has started installing trackside disconnection switches for maintenance staff to use to isolate the third rail more safely.
I have drawn all three of these details in a CAD program to have them 3D Printed:
Other typical lineside cabinets are available as follows:
44-560 Bachmann Scenecraft Lineside Cabinets
SSM320 Wills Modern Relocatable Equipment Cabinet Kit
Further Reading
Although not 3rd or 4th Rail related check out Simon's book Colour Light Signalling for Model Railways.
ISBN: 9781785006258 Published in October 2019.
