I’m currently planning a layout on wich I’ll be using Peco C55 tracks and turnouts.I’ve purchased both double crossovers and double slips that I intend to use to maximize the space I have,although not necessarily prototypically though.But still,I’m curious to know if…
1)I’ve read somewhere that double crossovers weren’t popular amongst railways and that there were only a few if any that exist on prototype railroads.Personally,I don’t know of any.Is this right?
2)Are double slip turnouts a “yard only” feature or can they be found on mainlines or secondary tracks where speeds are somewhat reduced obviously?Are they more popular in passenger service yards or are they generally used by freight trains as well?
3)Did DS’s exist during the steam era and if so,were they limited to smaller steamers?Could they handle the longer wheelbases like Decapods,Northerns and even the articulateds?Just curious…thanks.
Jack,
Double Crossovers and Double Slip Switches are used whre real estate is tight. Places like large passenger terminal use them quite often. I have seen a Double Slip Switch at a Junction(Manly Twr), and in a freight yard(Mason City).
All of these existed in the ‘steam era’. Normally, a railroad will just use a pair of crossovers and not waste the money on all of the frogs in a Double Slip or the Double Crossover.
Jim
In a situation where a prototype railroad is trying to shoehorn ten tons of specialwork into five tons of space the track designers will use double slips, lap switches (AKA 3-way switches,) crossovers single or double… Somewhere in the archives is a photo from Jersey City (I think) showing a LOT of complex specialwork, including at least one double crossover with a double slip at each corner.
Most DSS installations were in passenger terminals and yard throats, where unlimited use of space was not an option. They were speed limiting, but no more so than individual turnouts of equal frog number.
One major use of DSS was and is to straighten out the snakewiggles of sequential crossovers when a train has to cross multiple parallel tracks on a route which could be switched to access any of them. In that situation, double slips actually allow a slightly shorter time of passage, and much reduced side loads on the passengers aboard.
Leaving the North American continent, I once stopped at a station which had an interesting combination of an asymmetrical double crossover with a double slip at one ‘corner.’ The specialwork was located between a bridge abutment and a tunnel portal on a steep continuous grade. The main line ran from the bridge straight through the double slip, across the diamond and then took the straight side of the turnout at the opposite corner, which had its headblock ties just outside the tunnel portal.
Trains stopping at the station had to make a switchback maneuver. Upgrade trains would take the curved side of the double slip, stop short of the bumper at the end of track, then back straight across the DSS to stop at the platform with the markers just clear of the end-of-track bumper. Departing, it would take the other curved route through the DSS and head into the tunnel. Downgrade trains would take the curved side of the tun
I will assume that by double crossover you mean a pair of crossovers that overlap with a diamond in the middle. In 30 years I have only seen 2 of them, one in the throat of a passenger terminal and one on the crest of a double lead hump. Every other set of “double crossovers” was two crossovers back to back.
They are most commonly found in the leads to passenger terminals. There are very few on mainlines, especially now. Most railroads would replace them with conventional switches if they could to reduce maintenance costs.
They were way more common in the steam era when maintenance costs were not so high. Most of them where in passenger terminals and they were the same number as conventional switches so they were no larger or smaller than any other switches in the leads.
if you go to the Bing Maps site and enter Mitchell Illinois, you can do a bird’s eye view of the trackage at Lenox Tower. just north and a little west of the brick tower building you will see a slip switch of some sort where the double track main splits and heads off toward East Alton. if you follow the main line south into Granite City, there is a slip switch right at Niedringhouse Ave where the tracks turn to the south and head into the TRRA yard at Madison. a lot of the trackage at both locations has been taken out since i worked at those locations but it looks like the puzzle switches are still there.
keep in mind that some railroads were paranoid about having facing point switches of any kind on their high speed main lines and often installed trailing point crossovers on double track that required a train to pull past the switch and back over onto the other main in order to let another train pass them.
i don’t recall seeing a double crossover outside a yard in all my carreer although St Louis Union Station had a bunch of every type switch imaginable. it it’s day it was a thing of beauty although at first glance it looked like somebody had been drunk for a week before they laid pencil to paper.
grizlump
I’ve seen these at New York Penn Station[:)]