As I spent time bashing my head against the underside of the bench work of Queens Wharf this week, as I wired in some turnouts I’d removed a while back, an idea occurred to me. Perhaps the idea got in there from banging my head but it’s not a theory I’m keen to test! 🙂 I’d been doing some rethinking about what I wanted to do with the space I’d created for the short NG line I wrote about a few months ago. The problem was that I just couldn’t get what I wanted to fit either in a practical, track layout sense or in an operational sense. The benchwork for the NG extension had sat untouched and unchanged for several months as I’d gone about making models and planning for the next round building and track laying to the broader layout. So I took the decision to remove the NG from the plan. It will reappear at some point down the track but not as a part of the layout.
However while my plans for NG track laying had stalled I’d left the benchwork for it in place and started to think about whether to remove this or see if I could incorporate it into the SG network as an industry siding or modest industrial complex. This benchwork forms a narrow peninsula that run down the middle of one of the operating “wells” either side of Morpeth and the storage yards/coal branch.
The minimum radius on Morpeth is 1.2m on the branches and 1.5 on the main. The most logical place to branch off from the main onto this orphaned benchwork would be from the yard you can see on the left in the above photo however, there simply isn’t the space to get even a 1.2m (4′) radius curve to bend around and emerge in the approximate centre of the benchwork. I could lay track on this peninsula and leave it unattached from the rest of the layout but this would defeat the purpose of doing any work on it so I was considering tearing it down and setting the segments up in my work room where I’d install some NG track. It was at this point that the thought struck me that if I could somehow lay track from the other direction (coming in from the far right in this photo) then this would allow a connection to the rest of the layout and add extra operational possibilities. The only problem with this solution was that the coal branch rises over the exit from storage at this point, thus precluding any opportunity to raise this track over the main, and the main itself sits at about 45 degrees to the track extension that would be needed, so any thoughts of just installing a new left hand turnout into the main and running some track down to the benchwork was also blocked.
What to do?
What did the prototype do when two separate lines needed to cross but a bridge or cutting wasn’t practical or cost effective? A diamond crossing of course! But hang on, this would be two curved lines (one is 1450mm radius and the other 1500mm radius) crossing at about 40 degrees to the other. I’ve never built a diamond crossing and, in spite of being involved in this hobby for over 40 years, have never used such a crossing on any layout I’ve ever been involved with so have no idea of how they operate. Did Iet any of that stop me? No way! 🙂
I did what I usually do in these circumstances and consulted my wiring bible – Easy Model Railroad Wiring by Andy Sperandeo – to find out how to isolate and set diamond crossings up electrically to see how this would impact the construction.
It might be legitimately asked that, as I’m not familiar with the diamond crossing as a species of track,wouldn’t I be more concerned about how to make the thing rather than how to wire it up? This is a legitimate question, however I had little doubt that I could in fact construct the crossing and get trains to run through it. What I didn’t know much about was how I was going to wire the thing up when it would be sitting on one leg of a triangle that is protected by an automatic DCC polarity switch which itself has to operate in harmony with short circuit protector for that zone of the layout. I suspect that this might be cause for conflicts but damn the torpedoes I say: full steam ahead! Andy had no advice to offer on this topic but he did show how to build the crossing to allow no short circuits. All I needed to do was build the crossing. Wiring it so that it worked could be confronted later.
I’ve been using a UK program called Templot for a couple of years now and generally find it extremely useful. It allows you to design just about any type of trackwork your heart desires, expect for a diamond crossing with curved legs of the angle I needed! Evidently, according to a little pop up box that would appear when I clicked the appropriate button to “Make Crossing”, the prototype didn’t use crossings of this angle so therefore I wasn’t having one either! 😦 &^%!@# the prototype! I did what I usually do when I computer tells me I’m not allowed: I went old school. I printed out the bits I could and cut and pasted them together on my dining room table which provided me with a perfectly serviceable paper template to allow me to lay out the sleepers accurately. Cutting up the track and pinning it to the sugar pine sleepers I get from Gwydir Valley Models was a relatively simple task, after checking Mr Sperandeo’s book to ensure I had electrical gaps where I needed them.
All I need to do now is install some new track bed and a new left hand turnout into the mainline to allow access to the crossing. Wiring it up may turn out to be a bit of a challenge but that all remains to be seen in about a week’s time.