The electronics
That constant flow of trains, to and fro under that great roof, is down to a control system that’s far more sophisticated than the typical DCC system. DCC was still in its infancy when the layout was started and although it could provide all of John’s operational needs, it lacks the tactile function of the huge control panels. Basically, John can fulfil his fantasy of being a signalman, controlling trains in and out of the terminus!
John is a retired telecoms engineer, as is fellow electronics whizz Geoff Peters. Their combined training and skills have allowed them to develop some incredibly sophisticated electronics.
It’s hard to make electronics sound, well, interesting but spend a few minutes in John’s company, listening to him speak of the systems under ‘Lime Street’ and you’ll be shaking your head in wonderment rather than bewilderment!
As an ex-telecoms engineer, John is just as keen on fault finding as he is on making things work in the first place. The wiring diagrams fill at least three thick ring-binders.
Should the power go out in an exhibition hall, you might find that one of the control relays for the Fulgurex point motors has released but the point itself hasn’t changed. And, if a locomotive has been left straddling a point, you are, as John eloquently says, “knackered”. When the power is restored, the point would move under the loco. However, all the points can be tested and reactivated at the touch of a button once the points have all been checked. All of the point motors can be cycled too, in order to find the ones that are sticking and all the possible routes can be checked at the touch of a button that initiates a route-testing routine.
There are a staggering 72 25-way plugs and sockets under the baseboards.
“You want to make sure that you’ve put all these plugs in correctly,” says John.
“If you get one wrong, you get all sorts of problems.”
That’s why John has included something called a ‘cable integrity lead’ (CIL).
“Every 25-way plug has a wire going through it which is daisy-chained to form a circuit,” John explains.
Essentially, if you allocate a different pin on every plug and socket to the cable integrity lead, when everything is connected, it forms a circuit. If a plug is wrongly connected, the circuit is incomplete, which, on ‘Lime Street’, is highlighted by a blue light. Then you can go and find the fault. As John says, you can use a cable integrity lead on any layout.