Last June, on a visit to the Illinois Railway Museum, I ran across a diamond that the museum has put in (see photo). I have mentioned installing a diamond at our museum to be used in conjunction with our interlocking tower. There are those members however, that say that there are too many things that have to be installed besides just ties and spikes. I could understand that thinking IF the diamond was going to be used for high speed and/or heavy duty, as most diamonds were in regular service on common carrier railroads. This of course, would not be the case at our museum, as I don't think the future plans are at IRM with the diamond shown. So my question; are there railroad museums out there that have installed diamonds, and what exactly are the issues with their installation, if any?

Thanks.


Les Beckman (Hoosier Valley Railroad Museum/North Judson, Indiana)

That is the second crossing installed at IRM. If you look at appx. 2 o'clock on this map, you will see the first, which has been in service since the eighties:

http://www.irm.org/tour/propertymap.html

It sees regular service on the streetcar line, with occasional diesel locomotives switching the barns on the other route, I've not been active for a good many years, but as far as I know, it takes no more maintenance than a turnout.

Dennis -

Thanks for your note, and the map of IRM. When I rode CTA 3142 on the streetcar line that day, I didn't even realize that we had gone through a diamond. I noticed the one in the photo because we went next to it, but not through it. From the looks of the other diamond, it has to be somewhat similar (angle-wise) to the one we have at HVRM (photo below). Would be interested in knowing construction particulars in IRM's installation of their two diamonds.

Les

Such as what? Are they talking about the interlocking end of things? As for the diamond part, if your crews can build a turnout, they can build a diamond. There are some special plates, just like a turnout (switch) but presumably your diamond includes them.

The only really tricky part is that the alignment of both tracks has to be spot on, or you'll get doglegs or "angle points" entering and leaving the diamond.

For a typical museum speed operation I don't see the problem. I have to admit, I've never installed a diamond on a museum operation, but I have installed a couple on a local shortline, and they weren't a big deal.

Branford Electric Rwy. Ass'n. - Shore Line Trolley Museum had a new diamond custom build to them in 2 parts, for shipping purposes.. They also bought a used diamond, as a collection of frogs and guard rails, but it hasn't been used, yet.
Delaware Valley Short Line trolley museum in Tansboro, N.J. had 2 almost 90 degree crossings in use in the 1960s, but they were used girder rail.

Here is a somewhat foreshortened telephoto view of IRM's first diamond:

http://www.irm.org/gallery/album195/adp

This is looking down the barn lead; the car line runs right to left.

This crossing was built with the one leg curved; came out of the Commonwealth Edison California St. generating plant when it was being dismantled in the early seventies. IIRC it is ASCE 80# rail (8040). The track plan was developed specifically because we had the crossing when a property planning session addressed the fact that we did not have enough "steam road" radius storage buildings.

I'm sure the nattering nabobs of negativism that Les is talking about are citing engineering texts that plainly state that you can't put enough timber under a crossing to adequately support it under HEAVY MAINLINE TRAFFIC, and railroads over the years have put all sorts of steel and concrete structures under mainline crossings to deal with this problem, but hey, we're not running heavy mainline traffic. As I recall, this crossing was placed on the standard IRM yard track construction of the time; sprinkle 6" of bank-run gravel on the grass and lay out the ties. I'm sure it has had numerous lifts over the years to tamp more rock under it, but that's the way all the early museum track was... the longer it's in service, the better it gets. Keep in mind that those diesels you see in the photo, plus the U.P. turbine that is farther west in Yard 5, all had to come in over that crossing, because it's the only way in.

it seems strange it deadends like that but its part of the future planning at IRM, so there ya goes with the rest of the story.

Engineering has nothing to do with it, its smiple matter of man power and priorities.

Yep, looks like it will provide a switching lead for future storage yard 12 and perhaps a bridge over the creek.

Les,

One of the few concerns might be in respect to any signal system you possibly have at your museum. Crossings like this, just like on a model railroad, short the rails together. If you have a signal system, you need insulated rail joints on all rails with bonded jumpers around the crossing to maintain signal circuit integrity.

There should be some of the track and signals guys that could explain better than I can.

Dave Crow

Thanks Cory. That's good to hear.


Les

And of course there is the TRAINS article on this subject this month.

A bridge over the creek has to come first, there isn't not enough space to put the switch and still have headroom to clear the switch.

Or, don't insulate the components of the diamond, and simply have insulating joints on all 8 rails entering it. The diamond proper becomes a black-hole in the signal system, but a car is long enough that it'll always have one truck on an approach circuit. Anything too short is going to be MoW equipment or a Birney, and those are too light to reliably shunt anyway. In fact, most MoW equipment insulates the wheels.

Anyway for us at museums, we are vanishingly unlikely to put a diamond out on our "main line". It will certainly be in terminal areas, as at IRM, on our plot of land to solve topological problems of getting tracks into possible carbarn locations.

At the Nevada State Railroad Museum in Carson City we recently replaced two diamonds.
The old diamonds had developed cracks in the web of several rails. Putting in new diamonds alleviated this issue and allowed us to dual gauge the track. Both tracks are on curves.

Despite there had been diamonds there for 20 years (so the ground is stable) and our having tamped rigorously the diamonds still settled. They are built on ¾” plates which sit on wooden ties. All the ties are new as is the ballast. The plates make it difficult to tamp even though they are skeletonized.

Harmer built the diamonds in 2009. We purchased two with an approximate cost of $60K each. They were built in 90# rail, bolted, and plated. They came as kits and we had to assemble them.

Lining and leveling two tracks on a curve and a grade is a tedious but a tenacious man can prevail.

Chris DeWitt