Once past the milestone of trains running for the first time on Mark 2, I have returned to the storage loops. These were laid a while ago, but not wired. To recap there are 10 storage loops approached from the Down direction, a dumbell to reverse them and a return line to get them back onto the continuous run, but in the Up direction.

The entry into the loops comes off the Down continuous run. Its a straight foward ladder of electro frog points. So with a few feeds off the down bus and common return bus, plus frogs switched from micro switches, that is all normal stuff.

Similarly, the exit points ladder is straight forward, but the connections are to the up bus and common return. This ladder leads onto the dumbell and then the return line, which leads onto the Up continuous run. Of course because it's effectively a reversing loop through the dumbell, the common return needs to change from the outside rail to the inside and I have chosen for this to happen just before the exit ladder (so the common return is back on the outside (furthest) rail after the line has swung round the dumbell.

If you have read some of my early posts on Mk 1, you will know I originally just had one isolated section at the end of each storage loop. The loco was driven in on the Down controller and stopped as it passed into that isolated section. I then planned to have a push button or similar to connect that section to the Up controller to allow it to be driven out. The theory didn't work in practice due to back feeds through the common return, loco wheels stopping over the isolated breaks and all sorts of unexpected things. I got over it by adding a central isolated section in each loop as well. The process then involved adding 2 sprung loaded dpdt switches into the panel. One switches the central section feeds between Down and Up controllers (changing the common return as well), the other switch alternated the end sections betwwen Dead and Up controller. It worked, so the proven process was:- the switches wee held over in the Down position so the loco is driven in on the Down controller, through the central section (connected to Down), and stopped in the end section which is Dead. The switches were allowed to spring back to centre/dead position. For a train to leave, the switches were held over to Up position and both the central and end sections were then connected to the Up controller (the central section was also connected so there were no issues with wheels stuck over the opposite polarity part) and the train was then driven out on the Up controller. Once the loco is over the points, the switches were released to the centre Position.

It worked before, so I have done the same with Mk 2.

The only other complication is that before, I used insulfrog points at the exit and they selected which exit section was powered. The other loops remained isolated. With electrofrogs I don't have that, so I need a selector switch to choose which of the 10 loops is powered. I need that to always be in accord with the route selected by the points, so I decided to use a 3 pole rotary switch : 1 pole to select the route through a diode matrix (as with Mk 1), and the other 2 poles to power the live feed and common return for just the selected loop. I was not going to leave all the common returns connected to each other and have the ghost drivers all over again. The downside is that its 20 wires for the feeds and 10 for the routes, never mind the central sections and entry ladder.

The entry points are also one a rotary, but only a single pole: just 10 wires.

To operate the panel, once the route is selected by turning the rotary, the red square button below it is pressed which fires the CDU through the route selector and diode matrix. More on that later.

So, with that theory worked out, I built the Control panel.

Looking at the panel, the rotary on the far left selects the entry to the loops (Down). The square button below it fires the points. The two switches in the centre are then held over to the left (towards the rotary which has been used) as the train enters the loops, until the train stops in the loop.

The rotary to the right of this sets the exit (Up) loop and the switches are held over to the right until the loco has run onto the dumbbell.

Moving to the right of the rotaries, there are the switches for the points on the double junctions. These are servo operated and the dpdt switches also change the frog polarities. All fairly conventional.

Next along to the right we come to communication area of two switches and a tapper. The bell tapper rings the bell at Evenley (next station Up) and if the switch to the left of the tapper is pointing towards the tapper, Evenley will take control the Up line and drive trains out of the loops and onto the Up continuous run and then up the incline to the station. That is the process for trains stopping at Evenley. If the switch points left, then Buckingham West will take control the Up line for non-stop trains. The notification to Buckingham West that he should start a train, is given by the other switch there. Operating it will simply sound a buzzer telling Buckingham to turn his controller. Buckingham cancels the buzzer with a switch on his panel and turns up his controller. In due course, when ready to leave the continuous run, the Fiddle Yard (Banbury) operator rings the non-stopper through to Evenley in the normal manner using the tapper on this panel. Evenley then rings it on to Buckingham West and when accepted, points are set and signals pulled off. When Line Clear comes back to Banbury / Fiddle Yard man, he directs the train off the continuous run at the double junctions and it goes up the incline, through Evenly and on to Buckingham West, all under the control of Buckingham West.

Finally, on the right is the Down controller : a Gaugemaster simulator controller. This is used to bring trains down from Evenley or through Evenley from Buckingham West if non-stop.

Although quite compact with only a few controls, the panel has over 60 connections on the rear.

The majority of the wires are off the 2 rotaries. The blue wires are the entry / down route selector wires going to the diode matrix. The orange wires are the route selectors for the exit / up ladder. In between them on the choc block are the 20 green and black feeds to each isolated end sections.

When the sprung polarity switches for the end and central sections, double junction points, frogs, up line power selector, buzzer, bell tap, feeds to the other panels (yellow), controller power and main bus feeds are added, it looks rather more complex.

Anyway, it works on the test meter. Now to fix it to the baseboard, wire it in, power it up and see for sure!

Now what's next? Track laying up the incline or diode matrix construction?

Rich