ddest thing. We’ve been running my diminutive Tuscarora Branch Line for two an a half years. Now, this tiny layout runs under Time Table & Train Orders (a method where trains follow their timetables but modify their efforts based on train orders from the dispatcher). Now, I’m not going to say that we’re perfect in our execution of the method – selective compression and all that. But it seemed to work and everyone likes the sessions. Orders got passed. It felt “railroady”.
So, here’s the actual track schematic on the west side of the railroad. Westly is the coal mine (and while there are two tracks pictured, it’s also coal staging so one/both tracks are usually occupied). To the East, Tuscarora is a passing siding under an interlocking tower (that controls turnouts and signals and also serves as a train order office). Note the signals, placed to the right side of each track. The red signal is the distant signal (which allows trains to enter the interlocking plant) and the blue signal is the home signal (which is set depending on turnout alignment and signals ahead). The black signals are simple interlocking signals.Tuscarora has a main and a siding, both heavily used in passing maneuvers.
We assume that Westly is a short distance (a couple of miles) from Tuscarora and generally the dispatcher will advance the flip-clock ten minutes to reflect the train’s transit time.
So how would this work? Let’s use the example – there is a coal train sitting in Westly, with a cut of stationary coal cars sitting next to him. In Tuscarora, there is a freight train holding on the siding. The way we’ve run this for years is that the interlocking operator sets the home and then distant signal to green. As the coal train travels the short distance (about two and a half real feet) to Tuscarora, the dispatcher will let the tower operator know if there are any orders for that train (and the train order signal is set). Once the coal train clears into Tuscarora, the eastbound signals are dropped, the turnout aligned and the freight on the siding gets a signal to proceed west into Westly. Nice and clean.
But then, one morning when I was shaving, getting ready to spend the day driving down to South Florida to give my TT&TO clinic to the Western Bay Club, my razor halted in mid-furrow. For two and a half years… we’ve been doing it… wrong!
Given the distance between the two towns (a couple of miles) and the fact that we are using old push-pull interlocking rods, it is unlikely (i.e. impossible) for a distant signal to be miles away from the operating tower. No, it should only be (at most) a quarter mile. This means that the way the railroad should be represented is as shown below…
Yes, the distant and home signal should be close in to Tuscarora, and the remaining five miles in a single track main (not how it actually works on the railroad, but it’s how it really should be represented). And this results in a dramatic change to how operations will work.
For example, that situation above, where coal in waiting to go east out of Westly and a scheduled train waiting to go west out of Tuscarora, we can’t handle it as we used to. See, what we were doing (with those signals spaced so far out) was running the layout, not as TT&TO with an interlocking, but as CTC (Centralized Traffic Control, where a dispatcher sets all the turnouts and signals).
Think about it – that coal train that is holding in Westly? He can’t move. Why? Because if he looks at his timetable (and he’d better), he’d see that he has a scheduled freight pulling out of Tuscarora right now. He has no signals out of Westly, no protection. He should wait in Westly for the freight to pass but as noted, there really isn’t room (that second track is for staging, not passing). That’s how TT&TO works. And right now, given the distance and running times between the towns, it makes it impossible for him to advance.
I’m working on a solution right now. Originally we had a bunch of pre-printed “pseudo” orders, mostly telling trains what they had to do in Tuscarora. And I’ve always known (in the back of my bean) that TT&TO is not about giving rights to trains to work in one town, but to allow them to meet and move efficiently between towns. So, right now, I’m ditching most of my old “busy-orders” and coming up with meatier orders – such as “Train XXX meet Extra YYYY at Tuscarora”. If you issue this to the trains as they enter Westly and Tuscarora, the scheduled train will have to wait for the coal to run down from Westly before advancing (with is a very basic TT&TO move). There are two other orders I’ve also got to incorporate. Right now, I’m gaming my operation session on a piece of paper with a couple of markers to see how it will work out. So we’ll see.
Yes, big changes are coming for one of the world’s smallest operational layout.