Quote:
Originally Posted by Foghut
We've been told on our NR briefing days that in future there will be a move away from track circuits towards axle counters on high speed lines, due to the signal sections being so long.
I've had personal experience of unreliable track circuits. Coming happily out of a cutting at 90 mph after travelling for over twenty miles on greens, the next signal which controlled a junction was red. There was no way I could stop in time, so that was a category B SPAD on my licence for evermore.
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I lost count of the number of cat B Spads I've had. I even had one last week when a signal went to red against me as I was approaching it because of a power surge at the signalbox controlling it. Its the cat A ones you gotta worry about.
I remember when the old chestnut of leaves on the line first made an appearance in the newspapers. I'm pretty sure it was something to do with the Pacer trains that had just been introduced. When I first learned the 143's, they had some sort of a track circuit booster fitted to them because the engineers figured they'd have trouble activating track circuits because the vehicles were so light and only had four wheels per unit. Unfortunately the booster system proved to be unreliable and units were disappearing from the signallers panels because of the leaves which is the reason why there were so many problems.
You are correct about the fact that axle counting is the way that Network Rail wants to move foreward. As far as I am aware, the only section of track that actually uses this system so far is between Toton and Clay Cross Junction near Chesterfield. This system is used in conjunction with a new radio system thats being introduced called IVRS (Interim Voice Radio System) which will replace the currently out of date NRN system and also be used instead of Track Circuit clips which will now become obsolete with the axle counters being used.
I am one of the few drivers on the network who has been issued with my own personal IVRS unit because I sign that particular section of track that the system is in place on. Being issued with my own personal unit is only a temporary thing because all trains will eventually have the units fitted as standard. Some have already been fitted to some Class 66's.
Here's a small report about the new masts being put up and how some people aren't very happy about them.
http://www.mastsanity.org/index.php?...=100&Itemid=44