Traffic density

Discussion in 'Model Rail Operations' started by Triplex, Aug 31, 2005.

  1. Triplex

    Triplex Active Member

    On the prototype, how many trains can a one- two-, three- or four-track mainline handle per day? Under TT&TO, ABS, or CTC? I know the answers will be variable, but I'd like to have some idea.
  2. MasonJar

    MasonJar It's not rocket surgery

    In the 1920s, the Grand Trunk line that ran from Depot Harbour to Ottawa (former Ottawa, Arnprior and Parry Sound) ran an average of 1 train every 20 minutes on a single line.

  3. Triplex

    Triplex Active Member

    I just realized I should make things clearer - I don't just want to know the maximum each type can handle. I also want to know the minimum number that it's worth multi-tracking for.
  4. MasonJar

    MasonJar It's not rocket surgery

    I think that double-tracking may come about as more of a convenience and a way to reduce risk - e.g. westbound on track 1, eastbound on #2 ONLY. There are very few sections of track that are tripled or quadrupled, and they seem to be at bottlenecks like grades or so on. I don't think you'll find much triple or quad track across the praries, for example, where it is easy to haul trains at speed.

    Sorry I cannot shed any more light on this. Interesting subject though - it should reveal a bit more about the railways' planning process. They are after all in this for the money, and quadruple track costs a lot!

  5. Yard Goat

    Yard Goat New Member

    I can't recall seeing a formula for traffic density vs. number of main tracks in any of my many railroad-related books. One that might have the answer is "The Railroad: What It Is, What It Does" by John Armstrong, which I don't own and which may be hard to find.

    The easy way to sidestep any guessing is to either model a specific segment of a specific prototype--using the same number of main tracks as it did--or at least emulate the practices of one or more prototypes. If I was freelancing, for instance, a railroad that was set in the Northeast Corridor, I'd consider double, triple or quadruple-tracking. If I was building a model railroad set in the west, I'd probably stick with single-track.
  6. Triplex

    Triplex Active Member

    Yes, I know triple and quadruple track were never really common and are rare now. That's why I wonder - how many trains does a line need to warrant them?

    Let's say I was freelancing. Then yes, I could make the number of mains appropriate to the locale and era. But then, how many trains would I run in a fast-time day? That's why I want to know this.

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