TC Calcs Britain vs Russia

[yuriy]

Hello,
Could anyone give me some links on the most complete books and guides on calculating railway track circuits in Britain.
I'm trying to generalize the calculation methods that are used in Russia, with those used in other countries. I decided to start with Britain. Among the material that I could find, including the present site, I have realized that the general approach is very different. In Russia, there are five mandatory modes of operation of the rail circuits: normal, shunt, control, short circuit and continuous cab signalling mode. Each of the modes is calculated in a certain way.

Waiting for response

[Jerry1237]

Welcome to the forum.

There is plenty of information posted on this forum as well as people attempting questions practising the exam. Additionally, the IRSE produce several text books that contain much good information.

[PJW]

Hello,
Could anyone give me some links on the most complete books and guides on calculating railway track circuits in Britain.
I'm trying to generalize the calculation methods that are used in Russia, with those used in other countries. I decided to start with Britain. Among the material that I could find, including the present site, I have realized that the general approach is very different. In Russia, there are five mandatory modes of operation of the rail circuits: normal, shunt, control, short circuit and continuous cab signalling mode. Each of the modes is calculated in a certain way.

Waiting for response

In the UK mainline, track circuits are not used to provide continuous cab signalling, although the Irish Republic (Eire) does use what they call CAWS on some of their lines around Dublin.  The early automated London Underground lines such as the Victoria line did utilise speed codes, but this system has since been replaced.  The High Speed line (Channel Tunnel Rail link) uses the French TVM430 that does provide speed codes via the track circuits, but that whole line is rather more an extension of French practice to reach London rather than what is generally thought of as British!

For day to day railway application, no one does TC calculations for project work or maintenance work. Obviously the designer of the track circuit feed and relay equipment must do so, but the vast majority of signal engineers just take their product and install and test it according to the product information.  The IRSE exam does include TC calculations so that people are aware of broad general principles to get an intuitive understanding of their operation including associated hazards and faults.

You'll see in the calculations that:
the condition of maximum energisation with no train and perfect insulations is considered, 
the condition of varying "ballast resistance" is considered,
the condition of the train shunting the track is considered (the "drop shunt" needed to cause the track relay to de-energise having previously been fully energised),
the condition of the removal of the train shunt is considered ("pick up shunt" that permits the track relay to energise having previously been fully de energised.

I guess that these must relate in some way to the modes of operation that you have listed; perhaps you could explain a little more about what each of the names mean......

[yuriy]

But firstly I'd like to tell why I need exactly a book or any reference book. All the information we can find in the internet, including on the present site, are quite nice and interesting for selfeducation. But can you imagine, for example, that a kind of the texts are refered to in list of referances in some scientific articles. As for Russia I can present two the most respected books: N. F. Kotlyarenko "Electric track circuits" and  V. S. Arkatov, A.I. Bazhenov, N. F. Kotlyarenko "Track circuits of main lines".

In Russia in the main approach of designing of track circuits we use the theory of transmission lines and linear 2-ports networks. Such kind of approach can look a little bit overcomplicated, but in fact gives a lot of opportunities like opportunity to optimise the transferring of the energy from feeder to receiver. In the first book I've mentioned above you can find that the input impedance of all the cascades connected directly to rails should be equal to the caracteristic impedance of track for DC. As for AC the input impedance of general load connected to rails should be equal to complex conjugate value of the caracteristic impedance of track.

Now the regimes.

Normal regime is a regime of operating of fualt-free non-occupied track circuite which assurs that track is "non-occupied" is reliable mode. For each regime the wost conditions should be assumed. For normal regime the worst conditions are the min value of ballast (1 ohm km for lines and 0.5 ohm km for stations) resistance and max value of rail resistance. The result of calculation is the U_min of generator that assurs the reliable mode of normal regime.

Sunt regime is a regime of operating of fualt-free occupied track circuite which assurs that track is "occupied" is reliable mode. For shunt regime the worst conditions are the max value of ballast (50 ohm km) resistance, min value of rail resistance, shunt is located on the side of generator or receiver. The result of calculation is the U_max of generator that assurs the reliable mode of shunt regime. Resistance of shunt is normative and equal to 0.06 Ohm (excluding those ones utilising on hamp yards)

Control regime is a regime of operating of track circuite with broken rail which assurs that track is "occupied" is reliable mode. For control regime the worst conditions are the critical value of ballast resistance (calculated specifecly for each TC), max value of rail resistance, rail is broken in the middle of track. The result of calculation is the U_max of generator that assurs the reliable mode of control regime.

Once the shunt and control regimes have been calculated we choose the final U_max. Applyng U_max for normal regime we assure that max value on the receiver will not damage it.

Short circuit regime is a regime of operating of fualt-free occupied track circuite with an axle is at the piont where feeder is connected to. For short circuit regime the worst condition is the final U_max. Generator should not be damaged in short circuit regime.

Continuous cab signalling regime is a regime of operating of fualt-free occupied track circuite that assures the reliable transmission of code on the most remote point of the track