Diamond crossings, How do they work?

Near where I live, there is a major project underway to remove what is known as the "the junction" in Toronto. It is a diamond crossing that consists of two CPR tracks going east and west and two CNR tracks going North and south to Union Station. Metrolinx bought up the tracks belonging to CN a few years ago and a huge project is underway to make an underpass crossing the CP tracks bypassing any need for a diamond crossing to increase there Go Transit service along that rail line.

Here is a before and after diagram of the layout of the Diamond crossing.



It makes me then wonder recently how do they work?

-What exactly is the procedure operation of a diamond crossing crossing between two railroads in North America?
-If two trains from both lines are approaching the diamond crossing at roughly the same time, Who will then get the right of way to pass it first?
-Which of the railways controls it and who is responsible for maintaining it?
-Can I replicate any of such rules in my Trainz routes?

jd_james said:

It makes me then wonder recently how do they work?

-What exactly is the procedure operation of a diamond crossing crossing between two railroads in North America?
-If two trains from both lines are approaching the diamond crossing at roughly the same time, Who will then get the right of way to pass it first?
-Which of the railways controls it and who is responsible for maintaining it?
-Can I replicate any of such rules in my Trainz routes?

Click to expand...

All of such is dictated by individual agreements. I would figure that the RR with more traffic (trains or tonnage) gets right of way, besides passenger. The RR that was there first will typically maintain the diamond themselves. Some railroads forced trains to stop before crossing, have the brakeman/conductor throw a lever to clear some gates (but at the same time locked him in the shed) until the train was past, at which point the lever was replaced, door unlocked, and the poor sap could signal a highball. FWIW, I was talking with some representatives of MRail at Railway Interchange 2013; I learned that the average expected life for a diamond is 3 years before it needs replacing, and at temperatures above 85 degrees, they need inspections 5 times a week; otherwise 2-3 times a week. And I do recall that there is a way to install such signaling systems in TRZ, however my feeble memory at the ripe old age of 20 can only tell me it is not included by default, and needs to be downloaded from the DLS; no clue on the name.

jd_james said:

Near where I live, there is a major project underway to remove what is known as the "the junction" in Toronto. It is a diamond crossing that consists of two CPR tracks going east and west and two CNR tracks going North and south to Union Station. Metrolinx bought up the tracks belonging to CN a few years ago and a huge project is underway to make an underpass crossing the CP tracks bypassing any need for a diamond crossing to increase there Go Transit service along that rail line.

Here is a before and after diagram of the layout of the Diamond crossing.

<Pics removed from quote>

It makes me then wonder recently how do they work?

-What exactly is the procedure operation of a diamond crossing crossing between two railroads in North America?
-If two trains from both lines are approaching the diamond crossing at roughly the same time, Who will then get the right of way to pass it first?
-Which of the railways controls it and who is responsible for maintaining it?
-Can I replicate any of such rules in my Trainz routes?

Click to expand...

Hi James,

These are great questions and hopefully I can answer them.

- Operating procedures for level crossing lines.

These are usually protected by a tower and or some kind of other interlocking control. As in this case, one company or the other owns the main line while the competing company has to ask permission to cross. This is usually done by calling a dispatcher who will then set the absolute signals for the crossing train green so the driver can proceed. From what I've read, sometimes a smaller short line has to wait on the main and competing line to give them permission to open a gate and set the signal switch (an actual switch on a light pole) to activate the mainline stop signals. This is a stop and go procedure and is not at all convenient.

- If two trains approach at the same time.

This is tied into the answer above. This is usually governed by who owns the tracks that the other line is crossing. In the case of your example, the CNR may have been the line there first and therefore the secondary line, the CPR in this case, has to wait and also has to ask permission to cross.

The maintenance is sometimes split between the two railroads, but it is usually maintained by the mainline owner.


As in your case with the two important lines crossing each other, this can cause a major tie up for the two companies as their trains have to stop and wait for another to cross, and or call for permission to cross if required. This is what is causing the big tie up on the crossover especially if one line is running long freights. For us this is fun stuff to watch and add excitement to our routes, but for the prototype this operation can be an expense not just in maintenance but also time wise when it comes to running and operations.

- Can I duplicate this in Trainz?

Yes, it can be done using a Diamond Crossing rule or the ASB Crossover Controller. Both of which are easily setup and work just like the real thing.

I hope this helps. I am not an expert at this, but have only read in various places about train operations.

John

You can also use "trigger multiple signals"

There was one three way crossing that I know of.

In the case of the crossing at West Toronto that you posted, it is controlled by the CP dispatcher in Montreal. They give VIA and GO trains priority, but they pay a premium for that. A lot of times if we are approaching in rush hour GO traffic, they will ask us what time we would clear the interlocking if they gave us the signals. At that point we a bit of math with our train length and the 25mph slow order over the interlocking while they working on the underpass, and give them the time that we could clear. If there is more than three minutes between the time we give and the next passenger train, they will take the chance and let us go. Less than three minutes, and we slow down and start pacing to get there after the passenger train has gone by. That way we do not have to stop on any public crossings.