diamonds

[pat390]

Not to sound dumb, but can someone please explain how diamonds are set up?

[JoeKoh]

pat
i'll give it a shot.diamonds are where one rr crosses another or in deshlers case one rr crosses itself.there used to be towers and tower operators(with dispatchers) that regulated the flow of traffic.usually the first rr at a diamond controlled the crossing.now most diamonds are controlled electronically. the I&O has to call the csx dispatcher for permission to cross the diamond in hamler.in fostoria ns trains usually run one both ways when they get clearance from "F" tower which is operated by csx.in leipsic its usually who gets to a block first that will control a diamond. I hope this helps.
stay safe
joe

[techguy57]

Do you mean how they are installed (Mudchicken would have a good answer) or how they work or something else entierly that I'm missing?

Mike

[pat390]

well I know their purpose but when I look at them I just dont get if there are moving parts involved like on a switch or if they work either direction at any given time

[techguy57]

Okay, much easier to answer now. No moving parts. They do essentially work in any direction at any time which is why signals are an important aspect of any diamond crossing. It is imperative to keep up the maintenance to them keep them properly alligned.

Like Joe said sometimes the RRs need to call in to dispatchers for clearance to cross whereas others such as Rochelle operates without dispatcher's orders and the first train to cross the signal sensor gets priority. Any other trains will have to wait until the diamond is clear and they get an all clear signal. Hopefully that helps.

Mike

[nanaimo73]

Here are some pictures you can look through
www.rrpicturearchives.net/srchThumbs.aspx?srch=diamond&search=Search

[pat390]

ok thanks guys, that cleared things up for me

[Big_Boy_4005]

Pat, here's a close up of a diamond. It is made up of 4 frogs, and some other bits of rail for running and guard.



When the crossing angle gets too sharp, it becomes necessary to have moving parts. The flangeway in the frog becomes so long, it can't keep the train from derailing. These low angle diamonds are very rare.

They shouldn't be confused with slip switches, which allow trains to travel between adjacent legs. A low angle diamond only allows a train to cross straight through.

[Murphy Siding]

Does a train have to reduce speed over a diamond?

[miniwyo]

Diamonds are Forever, duh! [:D]

[waltersrails]

From where i wacth yes in some areas and no at others it depends on the circumstance. Like up at effingham il yes because the diamond is rough and at Mt. Vernon il no because everything is good and tracks are clear hope this helps.

[Anonymous]

Some diamonds have moveable points; these are usually on very small angles (dictated by engineering considerations, location of intersecting lines, etc.), like 15 or so degrees. Frogs on angles that small have long spaces between the running rails, and the moveable points are intended to close them up.

Back in the glory years, the Milwaukee Road had a speed restriction in its Chicago-Milwaukee District timetable: "Reduce to 100 MPH over EJ&E crossing at Rondout." Amtrak still goes over the Rondout diamond at better than 70 . . .

Old Timer

[REDDYK]

Diamonds are NOT forever. It is my observation that diamonds are indeed a high maintainence item. Trains do not always have to slow for a diamond, but after a few months pounding and as the wear surfaces begin to deteriorate, you usually hear the crossing from blocks away. Pretty soon the slow orders show up and then the welders and or new parts are next. I have seen a double diamond total replacement in less than two years life span. Gary

[nanaimo73]

Those low angle diamonds must be special order. I would assume a spare would be kept close by in case of a derailment.

[mudchicken]

ANY crossing frog (proper name for a diamond) is special order, custom built. None are an off the shelf item. (rigid, railbound manganese or cast - they take time and considerable skill to assemble. If you don't take care of the structure beneath the steel, the crossing frogs wear out faster.

ALL are expensive ($400,000 and up for just the steel) and are the weakest structure on the railroad. Welders darned near live on the things repairing damage. If at all possible, you avoid placing crossing frogs at all costs.

Speed is a function of longevity of the trackwork and curvature. (impact loading)

[Big_Boy_4005]

MC, I know you are the forum's track expert, and I mean no disrespect, but that $400K price tag sounds a little steep, especially looking at the photo above. While each "crossing frog" (I learned a new term) may be custom the first time a pattern is made, after that it's a simple matter of repeating the process.

Even if you went in half degree increments from 90 degrees to 15 degrees, there would only be 150 different patterns to choose from, creating more of an "off the shelf" situation.

The frog design in the photo above is very clever. By removing only 6 bolts per frog, the casting can be lifted straight up. Then it can actually be rotated 180 degrees, moving the worn points to the inside, thus doubling the life of the casting. My guess is that the other parts don't wear out nearly as fast as the frogs, which makes the idea of a lift out replaceable frog so appealing. Maybe this is something new.

A little more close inspection (I have more photos that aren't uploaded to the web) reveals that this diamond is made up of 18 parts, not including nuts, bolts and plates. Of those 18 parts, there are only 6 different shapes. Many of those parts may be regular rail machined down, and not special castings. The frogs may be the only castings, but I'm not sure.

A little background on the tracks in the photo: the line with the obvious traffic pattern is the CN's only access to St Paul, ex SOO, ex WC. The line with the rust is BNSF, former NP main to Duluth. It is operated by the Minnesota Commercial, and is basicly an industrial spur serving a lumber yard in the town of Hugo 5 miles to the north, where the tracks end, and the right of way is now a trail.

From previous topics, we know that the railroad doing the crossing of an existing line bears the burden of maintenance for the junction. I guess it stands to reason that the NP got there first, because if they had to pay to maintain the crossing, they would have cut the lumber yard loose long ago.

[mudchicken]

For openers, one explosive hardened manganese casting = $80,000...you're looking at 4 and probably a spare....$55,000 for the engineering....and it's clear you have never worked in a rail planing mill (IronKen did at dear old Newton)

Cheapest x-ing frog I ever put in was a simple carbon/ rail planed frog...$280,000 which lasted all of 6 years before it was toast (Mission Tower-LA).....You need to visit CTM at Cleveland, Conley S&F or Meridian/ABC at Chicago some day...

Your over simplified view don't quite fly of having patterns, jigs and mill sand molds just lying around...The plans are kept, but that is about all. Re-ordering a crossing takes 6-9 months, order to delivery, and it is usually from scratch. Also there are only 4 vendors in the US that can build new crossing frogs and there are only about 6-8 planing mills left. There can be just enough change in crossing geometry to make those old plans invalid by replacement time.....

Rail crossing geometry almost never comes out at some even angle. None of the ones I was responsible for ever was. Never had a 90 Degree frog anywhere. You were dealt a given angle and you lived with it.

I'm afraid to think of what you think a package turnout costs[(-D][(-D][(-D]

[Murphy Siding]

Wow! How long does a crossing frog generally last?

[blhanel]

I have a question concerning a specific crossing frog- what's the angle of the frogs at Rochelle? I plan on incorporating it into my HO layout someday...

[Big_Boy_4005]

Wow MC, it boggles my mind to think of the cost of maintaining a railroad at those prices. My jaw is still on the floor, thinking that that one in the picture is double the price of the average house.

It's a good thing the only railroad I'm responsible for is a model railroad in my basement. I get off cheap by comparison. If I buy off the rack, diamonds are about $25. If I do them custom (few angles are available) it costs me even less, but I have to throw in a few hours of my time.

Chock this lesson up to economies of scale, my railroad doesn't make any money.[swg]

[mudchicken]

Now you know why railroads will do almost anything to avoid costly crossing frogs. (Or in JoeKoh's case set the unused frog aside for use later)

As far as crossing frog life goes - You are totally dependent on maintenance, tonnage, speed (impact), type of frog used and pure luck.

As a for instance, crossing frogs bought for ATSF's Southern California transcon crossing of the SP were purchased (If memory still holds true) in 1978 and were replaced in 1994. (Single track SP crossing double track ATSF).....We caniballized the remains of the old frogs and made a spare crossing frog to keep in the weeds in case of emergency (two of the manganese frog insert on that spare diamond were not the 1978 originals and several of the planed & milled rail pieces were not original either which should tell you something about the brutal existance of special trackwork)

[Murphy Siding]

You kept them in the weeds!!!!! It sounds like you should have kept them chained up to something quite stationary![:)]

[Big_Boy_4005]

Murph, nobody knows to steal them. Beside, they are a little heavy and difficult to hock.[swg] It's really more paperweight than my desk needs.[:O][:P][:-,][;)]

[bobwilcox]

QUOTE: Originally posted by Murphy Siding

You kept them in the weeds!!!!! It sounds like you should have kept them chained up to something quite stationary![:)]

I can see a posting on ebay for one 9.67 degree railroad frog. Minimum big $10,000.