Double Track Diamond crossing
- Thread starter macwilly
- Start date
It's not much different, I don't think. When I've signaled for double-track diamonds, I use an absolute signal for each direction traveled so that both main lines are signaled. So the trains don't collide should they meet up, I then use Boat's ATLS ASB controllers for the diamond crossings to control the signals so the trains aren't blind to each other.
John
John
G'day macwilly,
...assuming you're referring to 'standard' Up & Down "Double Line", where the direction of travel is determined by the line on which the train is travelling, the advice of "JCitron" notwithstanding, 'standard' BR practise would be to provide "Home" signals to protect movements in the 'proper' direction of travel and "Shunting" signals (usually "Ground Discs",) for movements across the points "in the WRONG direction"...
Jerker {
}
...assuming you're referring to 'standard' Up & Down "Double Line", where the direction of travel is determined by the line on which the train is travelling, the advice of "JCitron" notwithstanding, 'standard' BR practise would be to provide "Home" signals to protect movements in the 'proper' direction of travel and "Shunting" signals (usually "Ground Discs",) for movements across the points "in the WRONG direction"...
Jerker {
}G'day macwilly,
...assuming you're referring to 'standard' Up & Down "Double Line", where the direction of travel is determined by the line on which the train is travelling, the advice of "JCitron" notwithstanding, 'standard' BR practise would be to provide "Home" signals to protect movements in the 'proper' direction of travel and "Shunting" signals (usually "Ground Discs",) for movements across the points "in the WRONG direction"...
Jerker {
I have seen that as well over here in the US.
John
I use the Path Rule and associated Path Command by _mutton_, kuid2:71155:60006:4 and kuid2:71155:60007:4.
In Surveyor -> Edit Route build your route so that each track has a point or turnout in it. These can be (in UK terminology) catch or trap points, or "invisible" - ie made of a short section of invisible track with an invisible lever. Place these junctions after the crossing. Set the default directions of these levers to the dead-end invisible track. Place 4 signals on each track approaching the crossings.
Name the 4 junctions. For example if your tracks were to be named NS (for north-south) Up, NS Down, WE Up and WE Down, then the turnout levers could be named NSU, NSD, WEU and WED.
In Surveyor -> Edit Session, set up the Path Rule so that each path contains 3 (YES three) junctions - 1 for the route itself and 2 for the crossing tracks. For example, to set the route North-south Down, set the path to contain junctions NSD (set to through), WEU and WED (both set to the dead-end). Also set NSD as the release object (which is why we place the junctions after the crossings)
Thus when the driver command Path Set calls the route north-south down, it will only set the junction NSD to through if both WEU & WED are also free. It will then lock WED & WEU to the deadends, preventing any signal from clearing, and allow the train through junction NSD. When the train leaves the NSD junction, NSD and WEU & WED are released.
Result is a fully protected double-double-track diamond crossing.
I believe the only example left in the UK is just north of Newark, where the Newark-Doncaster section of the ECML crosses the Nottingham-Lincoln line.
https://www.google.co.uk/maps/place/Newark-on-Trent,+Newark,+Nottinghamshire+NG24/@53.0905786,-0.804763,152m/data=!3m1!1e3!4m2!3m1!1s0x487834455e4590d7:0x2fa6a5583441f3c3!6m1!1e1
In Surveyor -> Edit Route build your route so that each track has a point or turnout in it. These can be (in UK terminology) catch or trap points, or "invisible" - ie made of a short section of invisible track with an invisible lever. Place these junctions after the crossing. Set the default directions of these levers to the dead-end invisible track. Place 4 signals on each track approaching the crossings.
Name the 4 junctions. For example if your tracks were to be named NS (for north-south) Up, NS Down, WE Up and WE Down, then the turnout levers could be named NSU, NSD, WEU and WED.
In Surveyor -> Edit Session, set up the Path Rule so that each path contains 3 (YES three) junctions - 1 for the route itself and 2 for the crossing tracks. For example, to set the route North-south Down, set the path to contain junctions NSD (set to through), WEU and WED (both set to the dead-end). Also set NSD as the release object (which is why we place the junctions after the crossings)
Thus when the driver command Path Set calls the route north-south down, it will only set the junction NSD to through if both WEU & WED are also free. It will then lock WED & WEU to the deadends, preventing any signal from clearing, and allow the train through junction NSD. When the train leaves the NSD junction, NSD and WEU & WED are released.
Result is a fully protected double-double-track diamond crossing.
I believe the only example left in the UK is just north of Newark, where the Newark-Doncaster section of the ECML crosses the Nottingham-Lincoln line.
https://www.google.co.uk/maps/place/Newark-on-Trent,+Newark,+Nottinghamshire+NG24/@53.0905786,-0.804763,152m/data=!3m1!1e3!4m2!3m1!1s0x487834455e4590d7:0x2fa6a5583441f3c3!6m1!1e1
justinroth
Well-known member
I second the path rule method. It is the only way to do complex interlockings and to control certain scripted signals that do not respond to asb or trigger multiple signals rules.