Service rails
Posted: Sun Mar 27, 2016 10:20 am
In my latest save, I've been trying to make a track system with 3 tracks instead of 2. The middle rail would be my "service rail" which is purely for me to get around, and the outer two would be standard running rails for automated trains. No junction anywhere on the network would allow a train to get from the service rail to the outer rails or vice versa, and there would only ever be 1 train on the service rail in the entire network.
Reasons for doing so should be pretty obvious - it means I don't have to wait to pass other trains (except for brief waits at junctions if other trains are crossing my path) and if there is a jam for whatever reason I can get to the source of the jam by train instead of having to walk, or dangerously use the other track in the wrong direction.
Usually when we place rails we leave a gap of 2 rail-squares (4 normal grid cells) between between tracks because we may want a track to connect to the neighboring track. However, since in a service rail system there is no need for any track to connect to its neighboring track - only for the two outer tracks to connect to each other - so I figured it would be a good idea to compact the system, with only 1 rail-square between each track: track, space, track, space, track.
This seemed like a great idea, until I needed to make a T-junction. It turns out that with this design, the places you need to place signals in are exactly where the service rail goes!
I've been trying to think of ways to get around this, and so far have come up with the following:
1. Just space the tracks out normally (track, space, space, track, space, space, track) - but this requires 75% more space compared to a usual 2-track system, instead of only 25% more space
2. Have the service rail divert off to one side at each junction and return to the center afterwards - but this complicates junctions and looks ugly
3. Use hook junctions instead of T-junctions (assuming trains drive on the left, then when a train wants to turn right, it turns left then does a U-turn to avoid curved rail crossing the service rail)
4. Use rotaries at each junction instead of T-junctions
While I've tended not to use rotaries in the past, option 4 sounds like the simplest and best way to deal with it. Has anyone tried this before and can suggest which is best or has their own ideas?
Reasons for doing so should be pretty obvious - it means I don't have to wait to pass other trains (except for brief waits at junctions if other trains are crossing my path) and if there is a jam for whatever reason I can get to the source of the jam by train instead of having to walk, or dangerously use the other track in the wrong direction.
Usually when we place rails we leave a gap of 2 rail-squares (4 normal grid cells) between between tracks because we may want a track to connect to the neighboring track. However, since in a service rail system there is no need for any track to connect to its neighboring track - only for the two outer tracks to connect to each other - so I figured it would be a good idea to compact the system, with only 1 rail-square between each track: track, space, track, space, track.
This seemed like a great idea, until I needed to make a T-junction. It turns out that with this design, the places you need to place signals in are exactly where the service rail goes!
I've been trying to think of ways to get around this, and so far have come up with the following:
1. Just space the tracks out normally (track, space, space, track, space, space, track) - but this requires 75% more space compared to a usual 2-track system, instead of only 25% more space
2. Have the service rail divert off to one side at each junction and return to the center afterwards - but this complicates junctions and looks ugly
3. Use hook junctions instead of T-junctions (assuming trains drive on the left, then when a train wants to turn right, it turns left then does a U-turn to avoid curved rail crossing the service rail)
4. Use rotaries at each junction instead of T-junctions
While I've tended not to use rotaries in the past, option 4 sounds like the simplest and best way to deal with it. Has anyone tried this before and can suggest which is best or has their own ideas?
