(This was a response I posted to a question over at the Model Railroad Hobbyist Forums. Since it addresses some of my operating philosophy - especially with regard to using a fast clock - I figured I'd post it here too for reference. Thoughts & comments welcome, as always!)
I'm still relatively new to operations, but am trying to follow my prototype (New Haven RR in the late 1940s) as closely as possible. I've modeled a one-town segment of double-track mainline (with loops and staging off each end) and two branchlines. The branches are operated by three local freights (one of the branches is split between north and south halves), one of which also operates through the mainline town. There's one other local that works the mainline and does the bulk of the switching in the mainline town.
That's all by way of background. The locals are all operated by TT/TO and the two that are out totally by themselves on the branches are pretty straightforward (don't even really need TT/TO since there's nobody to look out for - except the occasional speeder or work train). However, the mainline local, and the local that operates partially on the main have to consult the timetable to keep out of the way of the mainline trains that come through the one mainline town I model. And that's where I get to this statement...
"Taking a prototype timetable and pasting onto to a fast-clocked layout is an almost certain recipe for problems.".... with which, as a general rule, I absolutely agree. However, it's only "almost certain" :) and actually depends. I took the New Haven's prototype TT and pasted a 4:1 fast clock onto it and it works wonderfully - but I suspect this is because of two very important circumstances:
- I'm only modeling one mainline town;
- The locals on the branchlines can take as much time as they need to do their work.
Now, the actual amount of time between trains is much less than it was on the prototype (naturally, since I'm using a fast clock), but during the entire 3 hour session, there are only three times where there's only 1 actual minute between trains (7 times there's 2min & 7 times 3min); otherwise, there's 4 to 21 actual minutes between trains. I typically have 2 guys running the mainline trains - one in staging at each end - and they "launch" trains across the Old Saybrook scene according to the prototype TT schedule. It's actually pretty cool to just sit there and watch the parade of trains go by, just like they did in 1948. And it's especially cool that I could use the actual prototype timetable times. (now I just need to figure out and model all the proper consists... but that's for another time).
Now, that's just the mainline trains - and so far, no problem using a fast clock. It does admittedly get a little more complicated when the locals are in town - they have VERY small windows within which to work. However, that's again where following the prototype closely saved my bacon. In Old Saybrook, there were "local" tracks on each side of the double-track main, so - for the most part - the locals can do what they need to do without interfering with the mainline trains. But when they have to cross over the main, they have only a few sufficient time windows within which to do that.
And here's where I did make one compromise: On the prototype, the locals are both in town at the same time around mid-day. Given that I'm using the fast clock, the windows of actual time available mid-day are pretty short. But since the locals are extras, I could plausibly have them in town during a time when they have better opportunities to get across the main. So - though a compromise - certainly in my mind worthwhile to get everything else I'm getting.
As for the locals out on the branchlines - admittedly, no fast clock needed there. But it's still cool to have. Others have pointed out that one benefit of the fast clock is that it makes your run seem longer. Well, the fast clock really shines for me on the branchlines since I can only model a handful of towns on each line. Using the fast clock, the locals finish their work and get back to their home terminal about "12 hours" after they start (3 actual hours). That passage of time, to me, makes for a real day's work.
Now, of course, YMMV - and I've said all along that my situation may be unique since my mainline town is operated in "British" fashion (one scene with staging off each end). And not everybody is willing to limit themselves to modeling one town (heh - I'm glad I have all the towns on the branchlines too!). But I think that circumstance at least would allow you to use the actual times your prototype used in its timetable. I for one find that to be pretty cool - but I'm admittedly a bit biased. :)