Hello all, it's been a long time since my last blog entry,- this is all down to problems trying to get a 'new fangled device' to work correctly, if you will permit me ,I will explain:

As you may know, Sproston has 4 hidden sidings/fiddle-yard. The operator of the station has no view of this, and in order to make the layout operable by one person, some form of 'train detection' is necessary.

I had been mulling this problem over for some time, and after some interesting and informative discussion on the merits of this method in the RMWEB forum under 'Electrics- non dcc', I eventually settled on a device produced by "BLOCKSIGNALLING". The det-8 photo-electric 8 channel detector.

This consists of 8 small photo-electric sensors mounted just below sleeper level, in the 4 foot and connected to a little "box of tricks" by the control panel and feeding its indications to 16 leds (8 red, 8 green) mounted on a small schematic of the hidden sidings. A ninth sensor is used as a light source reference indicator and is mounted close by, but not under any track. The other leds are paired up one red, one green to each sensor. If an object stands over the sensor, the corresponding led shows red, if the object moves away from above it the paired led shows green and the red one is extinguished. There are several more complex operating sequences available on this unit, it is very flexible.

I had arranged these sensors - two on each siding, one positioned before the bufferstops, where the locomotive would automatically come to a stand when driven into the siding (on encountering the railbreak/isolating section) and the other at the fouling point for each siding.

The installation took some time- and is still not complete - as I am waiting for replacement parts to arrive in order to rebuild it....

The wiring is quite involved, and as no suggested voltage for the leds was stipulated in the instructions, I chose 12v dc, as this was the recommended supply for the unit.

All went well until power-up then I realised something was wrong!

I should have been presented with all the leds on the small panel lit as an initial lamp test - not so, it was a random display, some were lit- others were not, I wobbled the wiring about thinking there was a dry joint, and the lights changed - others now lit and some more went out, at no time were they all lit.

Oh dear, more wiggling and wobbling and it all changed again, along with the realisation that pushing down on any led and/or moving the panel top also caused this 'disco effect'

So, what to do - I had used my standard layout wire - telecoms 7 strand, coloured and quite sturdy. There were a lot of wires, including all the negative looping for the leds in very close proximity under the panel, made worst by the fact that access was still required at a later date to wire up the rest of some already installed signal pushbuttons, (for Dapol Semaphores) this requiring some slack to be left to allow the top to be lifted clear and inverted, maybe this was causing the tails on the leds to make intermittent contact with each other?

There followed a total rewire of the panel, this time using more flexible wire, however the result was just the same as before...

With a heavy sigh, and resigning myself to rewiring for a third time I began again, this time using single strand flexible thin red wire, the type normally used inside control panels on the 'big railway'

Yet again the same symptoms presented themselves on completion, I was getting nowhere fast!!

I began testing each led - they all worked fine - then suddenly (it could either have been me, or static electricity - the orange neon on the 'box of tricks' stopped glowing/flashing...... all the leds went out) - this was new, ...then things began to get very hot and I burnt my thumb on it!

So, end game I thought, very obviously short circuit - switch power off (fire...), and send urgent email to manufacturer asking for help/advice.

They replied quickly and gave me some diagnostic tests to run, but the unit failed on the first one I attempted, so they very generously asked me to send it back, and said they would replace it - which indeed they have done - at no cost ! full marks to BLOCKSIGNALLING.!!

The new unit has now been installed - this time I am trying a different approach for the two separate return paths required for the leds, by using two spaced solid copper wires to which will be soldered the 16 returns,and I am in the process of buying 16 replacement leds (3v this time, as I have been informed by the manufacturer that the device has an internal resistor to prevent any led problems) along with new preformed cables and connectors to eliminate all the soldered joints and bare wire under the panel, whilst allowing some movement for its removal.

Hopefully the result will be an improvement - it might even work!!

Watch this space! as they say for the next update to this long running saga....

Regards,

SIGTECH (Steve).