Eastern Railroad Discussion > Railroad vocabulary question

These days we define the term "crossover" as a configuration of two parallel tracks connecting each other by using two switches (one for each track). This enables a train to change which of the two tracks it utilizes.

However, when I was a kid, I thought that the word referred to when two tracks literally crossed each other at the same elevation, without a train having the ability to change its path to the other track. Are the two track configurations both referred to as "crossovers" or is there another term that I am not familier with?

Another question I have uses the correct terminalogy. When the track between the two switches is an extended length (not just directly going to the opposite track), how long can it still be to be considered as a crossover? Or is it all a matter of opinion?



Edited 1 time(s). Last edit at 09/24/11 11:54 by sandpatch25.

The term "crossover" decidedly does not apply to the track configuration you describe. I believe technically that's identified as a railroad crossing at-grade, but the best known term for it is a "diamond" or "diamond crossing".

Which is different from "grade-crossing" which is used to describe a road crossing a railroad track.

CG Tower

toledopatch Wrote:
-------------------------------------------------------
> The term "crossover" decidedly does not apply to
> the track configuration you describe. I believe
> technically that's identified as a railroad
> crossing at-grade, but the best known term for it
> is a "diamond" or "diamond crossing".

You are both correct. "Crossover" is the proper term for a pair of switches which allow a train to cross from one track to an adjacent track. "Railroad crossing", "crossing-at-grade", or "diamond" are all correct terms for two tracks crossing each other......at grade!

Jon

All of the above are correct. But then, occasionally the term "crossover" is used in another way, such as "the crossover at Frost, Ca." Which is not at-grade, but a somewhat unique crossing of two rail lines using an overpass. In fact TO member lotharb recently made a post and photos of the Frost crossover on 9-22-11. So it may be a sort-of casual use of the term, but it comes up from time-to-time. :-)

And finally, just to throw in another question re crossovers, what's a universal crossover?



Edited 1 time(s). Last edit at 09/24/11 06:53 by moltensulphur.

A "universal crossover" is an arrangement of switches that allow trains to change tracks in either direction...or:

eh, just see Patches...

CG Tower

moltensulphur Wrote:
-------------------------------------------------------
> All of the above are correct. But then,
> occasionally the term "crossover" is used in
> another way, such as "the crossover at Frost, Ca."
> Which is not at-grade, but a somewhat unique
> crossing of two rail lines using an overpass. In
> fact TO member lotharb recently made a post and
> photos of the Frost crossover on 9-22-11. So it
> may be a sort-of casual use of the term, but it
> comes up from time-to-time. :-)
>
> And finally, just to throw in another question re
> crossovers, what's a universal crossover?



Edited 1 time(s). Last edit at 09/24/11 07:14 by CGTower.

CG's "drawing" didn't really work out, but his answer is right. A "universal crossover" is a set of crossovers that allows trains on one track to cross over to any of one or more parallel tracks. On a double-track main, this involves two crossovers; on triple-track, four; and on a four-track line, six crossovers are involved, such as in this example (ignore the gaps in the main lines):

___________________
___\___________/____
______\____/________
___/___________\____


The arrangement at Frost, Calif., is more aptly termed a "flyover" than a "crossover."



Edited 2 time(s). Last edit at 09/24/11 07:15 by toledopatch.

CGTower Wrote:
-------------------------------------------------------
> A "universal crossover" is an arrangement of
> switches that allow trains to change tracks in
> either direction...or:
>
> ________________________________________
> \ /
> \ /
> _____________\_/________________________
>
> CG Tower
>
> moltensulphur Wrote:Maybe I'm not reading the track diagram correctly, but how about a crossover where the two crossover tracks form an X between the two run-through tracks? (Usually found in areas of cramped rail space, like stations and terminals.) That's also a universal crossover, yes?



Edited 1 time(s). Last edit at 09/24/11 07:14 by moltensulphur.

moltensulphur Wrote:
-------------------------------------------------------
> > moltensulphur Wrote:Maybe I'm not reading the
> track diagram correctly, but how about a crossover
> where the two crossover tracks form an X between
> the two run-through tracks? (Usually found in
> areas of cramped rail space, like stations and
> terminals.) That's also a universal crossover,
> yes?

Since the "universal" part refers to the ability to get from one track to any other track, I don't think so, but I don't know what the term for that specific arrangement is.

What you're referring to, when the two crossovers overlap so that there is a diamond crossing between the two mains, in the transit industry is usually called a "diamond crossover". On a double-track railroad, it would also be a universal crossover.

But in my experience, on a double-track railroad the term "universal" is rarely used. More likely would be "single crossover" or "double crossover". "Universal" applies to a set of crossover on three or more main tracks.

And we haven't yet talked about "slip switches" or "puzzle switches", which combine the functions of diamonds and turnouts. These are normally found only in large railroad terminals, and are becoming scarce because they are hard to maintain. For the same reason, where possible diamonds are being replaced by pairs of crossovers.

For a slip switch or a diamond crossover, on normal double-track spacing 22-foot timbers are required in order to support the crossing and to keep the tracks in alignment relative to each other. These long timbers are hard to find, expensive, heavy, and very hard to handle (think eight trackworkers on four pairs of two-man tie tongs).

Yes, not sure what happened with that...whatever...lets try this.

CG Tower

---

toledopatch Wrote:

> The arrangement at Frost, Calif., is more aptly
> termed a "flyover" than a "crossover."

Technically speaking I agree with you on that, yes.

If you have 4 tracks, with the X arrangement between the two inside tracks, the X has to contain a moveable point frog (puzzle switch)

No, it doesn't. If the pair of crossovers between the two inside tracks is interlaced so that the leads cross each other, there's just a diamond.

shoretower Wrote:
-------------------------------------------------------
> No, it doesn't. If the pair of crossovers between
> the two inside tracks is interlaced so that the
> leads cross each other, there's just a diamond.


Somewhat academic, since diamond crossovers are very rare. Possibly rarer than puzzle switches, except perhaps in rapid-transit/light-rail applications, where they're relatively common to fit into tight spaces.

toledopatch Wrote:
-------------------------------------------------------
> shoretower Wrote:
> --------------------------------------------------
> -----
> > No, it doesn't. If the pair of crossovers
> between
> > the two inside tracks is interlaced so that the
> > leads cross each other, there's just a diamond.
>
>
> Somewhat academic, since diamond crossovers are
> very rare. Possibly rarer than puzzle switches,
> except perhaps in rapid-transit/light-rail
> applications, where they're relatively common to
> fit into tight spaces.


More commonly known as double slip switches.

I have a 96 year old retired Wabash conductor friend who also refers to any switch as a crossover. I was surprised when he referred to such at the end of a siding. I know it isn't conventional but he uses the term loosely as whenever you go from one track to the other--in this case from the main to a siding. I kid you not.

A pair of crossovers with a diamond to save space, as mentioned used mostly in transit, is not the same as a double slip switch. A double slip switch is conceptually two turnouts, point to point, shoved together. Their application was frequently in large passenger terminals so that when a train crossed over two or three tracks the cars diaphragms were much less likely to pass. I cannot quickly (or may never find) a picture to Tower One at St Louis Union Station, but a good aerial from the past would show it. The tracks behind the tower were numbered 52 (closest to the Station) to 58, and there were three sets of double slip switches that took a train from any one of the tracks behind the tower to a station track.