Friday 7th July
Kevern and Paul met up to reinstall the concentrator at Gotherington. Mike S went to Winchcombe We knew that the line to Winchcombe was still not usable so we had planned to "borrow" another pair just top prove it worked but it still didn't, we hadn't foreseen that we had a broken wire inside the unit at Winchcombe!
Problem is that with each concentrator we have had to commission them in stages and as each new stage comes on stream new faults can appear, including a faulty Krone strip at Toddington!.
By definition this is all done between signal boxes that are a few miles apart, it all takes time. So to eliminate the dodgy cable pr, we took the new Goth Unit to Winchcombe and it still didnt work over a few metres of cable. Eventually Kevern found the problem, a broken wire inside the Winchcombe unit so we are now confident that when the new cable is connected ( to get rid of a number old joints inside and around the Tunnel area, we should be "cooking on Gas" as they say.
In the meantime of course its the block bells backed up by the trusty dial- up Strowger PAX that will keep the signalmen in contact.
Monday 10th July
Kevern went off to Racecourse early this morning, I attended a bit later at Goth and was able to prove that the section between Racecourse and Gotherington now works Box to Box. When Goth is switched out then we hope that the system will work over twice the distance ie Racecourse to Winchcombe. Kevern has just one more choice relays with a lower operating current to try in that case, buts just be positive.
Perhaps I can elaborate further on the Box to Box design side. The original scheme for the SPT's was all Loop Calling, AC ringing (ROLI like POTS). But when you need to call between boxes we had a problem since the Calling Box couldn't send a loop and anything else would have needed bi- directional transmission bridges. The answer was to make the bridge so that it would respond not only to a loop from its own SPT's but also to 50v dc from the other box and we had to inhibit the AC ringing so that the sensitive electronic relays in the bridges were not destroyed by an inadvertent burst of 80vac.
Again it took time and was the reason why the system has been installed stage by stage but we do now seem to be getting there
No new pics this time, I'm sure you have seen enough of us peering at things!!