02-02-2010, 08:00 AM
(01-02-2010, 11:16 PM)Peter Wrote:(01-02-2010, 08:06 PM)Archie Wrote: Could someone please explain the operations if a TI track circuit, with regards to TTU's and ETU's.
Many thanks
The TTU and ETU are the trackside units that the rail connections attach to. The TTU carries out the electrical equivalent of the block ......
The key is not a single TTU but a pair of them separated by (for UK mainline rail sections on concrete sleepers) 20m of rail......
Peter
I thought I had a model answer to an exam queston on such a subject but can't immediately find it. Hopwever I did find two Powerpoint drawings that I did for it, so I attach these to illustrate Peter's description
PJW