Example of what I mean
- 20190311191752_1.jpg (452.24 KiB) Viewed 1142 times
Is there any reason I can't use 6 car trains on a 3-car blocked rail?
Is there any reason I can't use 6 car trains on a 3-car blocked rail?
Most of my trains will be 3 cars, but I prefer longer trains to more trains when its called for. I'm aware my intersection exits must be a full 6 cars, but it seems that there would be an advantage to setting everything else up as 3 train cars.
Example of what I mean
Example of what I mean
Re: Is there any reason I can't use 6 car trains on a 3-car blocked rail?
With 6-car exit blocks, I think uncongested traffic will generally maintain that 6-car distance at all times, because the leading train's got that much of head start on accelerating ahead of the following one. Any train that gets closer than 6 cars will have to brake to reestablish that distance for the next intersection exit, see?
So 3-car intermediate blocks would only make a difference when there's congestion, you'd just be packing more trains into a congested leg, I don't see how that helps get anything through that next 6-car-exit-block-throttled intersection any faster.
...hunh. I'm pretty sure this simple-looking setup allows deadlock-free 3-car intervals even in the face of 6-car trains by providing a bypass failsafe for 6-car trains that hit congestion on the way out:
The red signal at the top center, the bypass entry signal, is wired close-if red<2, i.e. it's open if and only if a train is actually occupying both 3-car straight blocks below it. So there's a train in the chain-guarded merge exit to the right, so no other train's got the merge reserved. There are at most two trains to consider here.
The one-train case is trivial, it's in both straight blocks and either another train will arrive after it leaves the merge exit (which will produce the two-train case) or it won't (closing the bypass). Only the two-train case is interesting: the leading train's in the lower bypass block, the following train's in the merge-exit 3-car.
Now, here's the trick: the bypass (upper) segment's not long enough for a 3-car train, not even including the rejoin curve, but the bypass plus merge exit pair is long enough for 6, so
So 3-car intermediate blocks would only make a difference when there's congestion, you'd just be packing more trains into a congested leg, I don't see how that helps get anything through that next 6-car-exit-block-throttled intersection any faster.
...hunh. I'm pretty sure this simple-looking setup allows deadlock-free 3-car intervals even in the face of 6-car trains by providing a bypass failsafe for 6-car trains that hit congestion on the way out:
- snap@T259392=5248x720-46.75-23,z2.jpg (135.53 KiB) Viewed 1132 times
The red signal at the top center, the bypass entry signal, is wired close-if red<2, i.e. it's open if and only if a train is actually occupying both 3-car straight blocks below it. So there's a train in the chain-guarded merge exit to the right, so no other train's got the merge reserved. There are at most two trains to consider here.
The one-train case is trivial, it's in both straight blocks and either another train will arrive after it leaves the merge exit (which will produce the two-train case) or it won't (closing the bypass). Only the two-train case is interesting: the leading train's in the lower bypass block, the following train's in the merge-exit 3-car.
Now, here's the trick: the bypass (upper) segment's not long enough for a 3-car train, not even including the rejoin curve, but the bypass plus merge exit pair is long enough for 6, so
- any train taking the bypass will occupy both bypass and merge exit
- because of the signal wiring no train will ever take the bypass unless congestion has caused a previous, leading train to brake, and
- since the bypass exit is guarded by a chain signal, any train leaving the bypass block is guaranteed to be able to enter the following rejoin-exit 3-car block too
- but: if a six-car train leaves the bypass block and can't continue past the rejoin exit, its back three cars will still overflow the bypass block and leave it occupying the merge exit:
- snap@T342368=5264x976-46.75-24.25,z2.jpg (146.6 KiB) Viewed 1132 times
- snap@T385291=6976x1328-72.5-26,z2.jpg (208.73 KiB) Viewed 1132 times