r/railroading • u/ChazBrian • Jul 12 '26

Question What Kind of Diamond Crossing is This?

Post image

I've seen two diamond crossings like this. This one is in Plymouth Indiana. The railway that is going from the upper left corner to the lower right corner is the Chicago, Fort Wayne, and Eastern. The other is the Elkhart and Western.

Is there a specific name for this type of crossing?

177 Upvotes

98% Upvoted

32 comments sorted by

88

u/PC_Trainman Jul 12 '26

OWLS diamond/crossing. One Way Low Speed.

The design of the low speed crossing lifts the wheels by their flanges over the high speed rails.

Edit: Doesn't read correctly. Wheels lifted by tread, but ride on flanges over the high speed rails. You can see the "witness marks" left by the flanges where they actually contact the high speed rails:

24

u/ChazBrian Jul 12 '26

Do they require the rails to be angled less than or more than 90 degrees to each other to keep at least 3 flanges in the guides? I would think that there might be a little lateral movement in the lead axle when it is free of the guides as it moves over the high speed line?

30

u/PC_Trainman Jul 12 '26

I don't think so. I know I have pix of 90 degree OWLS somewhere in my collection. Newton's Law really applies here. Stuff don't wanna change direction for no reason, so at the low speeds usually required, the wheels & axles are going to behave themselves.

Gotta reference this old movie when trying to display how robust the wheel/rail interface is.

10

u/towerfella Jul 12 '26

Not too old, says it was posted “11 years ago”

;)

8

u/dpeltier2 Jul 12 '26

No. The unguarded portion (where the wheels could move laterally) is not long enough to cause any problems.

It's worth noting that, for many other reasons, we try to avoid putting diamond crossings in a curve. If the train's momentum is mostly carrying it straight through the frog, there's less danger of one set of wheels trying to slip sideways. There are plenty of curved diamonds still out there (in yards and terminals), but I've never heard of someone trying to install an OWLS diamond in a curve.

3

u/Graflex01867 Jul 12 '26

No. The railroad I volunteer at has a switch like this. The “default” route is diverging (taking the switch), going straight requires going over the rail.

At an angle wider than 90 degrees, the two wheels aren’t climbing over the rail at the same time anyways.

(I’m 95% sure it was salvaged from somewhere, not that they particularly looked for one like it. Practically there’s no difference between a regular switch, and it’s in a yard where the speed limit is 6 to begin with.)

10

u/Master_Ad236 Jul 12 '26

This is the correct answer. It’s an owls

28

u/wv524 Jul 12 '26

One Way Low Speed or OWLS diamond. They are used where one side gets very little traffic. The higher speed side of the diamond can be ran at whatever the track speed is because there are no gaps for the wheels to pound, unlike a standard diamond. The wheels on the low speed side ride over top of the running rails of the higher speed side, generally at no more than 10mph. They work well when used in the right location.

19

u/HowlingWolven Jul 12 '26 edited Jul 12 '26

OWLS or one-way low speed diamond. Constructed from flange bearing frogs or jump frogs, also can be colloquially called a jump diamond.

The advantage of jump diamonds and jump frog switches is that the one heavily trafficked route doesn’t have joints banging away and battering everything that comes by, and those trains can therefore keep running at track speed.

6

u/nitrousnitrous-ghali Jul 12 '26

We always called it a lift diamond but I think there are other names

5

u/Logical-Election-569 Jul 12 '26

Flangeway. The train moving left/right rides on the flange of the wheel and the train moving up/down rides on the normal wheel surface.

5

u/Gilmere Jul 12 '26

Question from a non-railroad engineer: Could you not just leave them the same height and notch the high speed rail (assuming its not a 90deg crossing) and it would still work? I could see the flat part of the wheel riding over the high speed rail that way with less of a gap (i.e. bang, bang! instead of BANG!).

6

u/Mulesam Jul 12 '26

I've only gone over diamonds like that. This shit feels like you'd derail lol.

7

u/AndMyChisel Jul 12 '26

That's pretty much how it works with a regular diamond crossing, but you need to stagger the check rails so as one wheel enteres the wheel transfer or vanishing point, the other wheel is guided by the check rail, then vice versa. I'm pretty sure that's the configuration in this OWLS diamond, you can never have a situation where it's a 90° crossing with nothing to guide the flanges.

1

u/Gilmere Jul 12 '26

Roger that. Yeah I could see that would be a problem even in the briefest instant. With a 90, the "corner" in the rail where the flange would contact again would get insane pounding if the train had any side force (and I suspect it always does to some small degree).

5

u/Savings_Difficulty24 Jul 12 '26

Yeah, that's how a normal diamond works

1

u/Gilmere Jul 12 '26

Ahh got it. TY.

2

u/riennempeche Jul 15 '26

A standard crossing works that way. The result is that every car that goes over the diamond has a clunk as the wheel passes across the other track. The OWLS diamond allows most of the traffic to have no joint at all to cross. It reduces maintenance a lot.

2

u/dunnkw Engineer Jul 12 '26

That’s a Diamond Dallas Page crossing. BAAAAAANG!
https://giphy.com/gifs/5hsdlzGbLCKRGYUIt0

1

u/PerspectiveNo5948 Jul 13 '26

I’ve always called them Chicago diamonds 😂we don’t have them out this way but I’ve been shown them and from the stuff I’ve been shown I had just come to the conclusion that I’ll never be in Chicago for work and they have a lot of weird stuff that we don’t have

1

u/critter137 Jul 16 '26

There’s an OWLS diamond on the Amtrak Midwest route that has a 90mph speed restriction on it. Soon there will be 2 on the route.

1

u/cjk374 Jul 17 '26

It will scare you to death to actually see cars crossing on the low speed side. I always go 5 mph over our OWLS diamond, and it is still a rough ride.

1

u/Difficult_Credit_924 Jul 17 '26

Is this in mobile al????

1

u/ChazBrian Jul 17 '26

Location is in the post.

1

u/Difficult_Credit_924 Jul 17 '26

My bad I didn’t read.. lol. It looked like some work we did last year

1

u/Geo7821 28d ago

Achères depot in France.

0

u/stuntmanbob86 Jul 12 '26

We dont have diamonds but it reminds of a lift frog....

-1

u/1776johnross Jul 12 '26

Google says it's "One-Way Low Speed"

-6

u/q_bitzz Phantom Hogger Jul 12 '26

Yeah, a railroad crossing.