As expected, the local New York TV stations have had extensive coverage of the Metro North grade crossing incident. Last night, one of the repoters did a report on the third rail, 400 feet of which ended up breaking off of its supports and entering the lead MU car, shattering into shorter lenghts. The Metro North third rail is an under-running system, where the rail is hung from supports, and the current shoe presses up for contact.
During the reporter's story, he stated that this under-running third rail system is unique to Metro North. Is anyone aware of any other rail system that uses an under-running third Rail?
I'm pretty sure Philadelphia's 3rd rails are all underrunning. I think I remember in Ron Degraw's "The Red Arrow" that the Norristown 'Philadelphia and Western' was originally going to be overrrunning, that they had develpoped a shoe that was supposed to work on both over and underrunning, but never made it overrunning or changed to underrunning shortly after the line opened.
I'm also pretty sure New York City's subways are all underrunning.
I welcome any more knowledgeable folks with data to back them up to correct my impressions.
Patrick Boylan
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LIRR and NYCT use standard over running third rail. That is the shoe rides on top of the third rail. The do have a protection board above the third rail, some railroads do not have a protection board. Chicago is one that does not.
Metro North uses under running third rail where the shoe rides under the rail. The protection device has the rail inside of it and the shoe is on the bottom.
Thus on MNCR the ends of the third rails curve upwards to push the shoe down and under.
On NYCT/LIRR third rails curve downards at the end to pus the shoes up to the top of the rail.
This would seem to make it easier for someting to snag under the MNCR rail, but less likely not to snag the other sort of rail. I do not suppose this really is the case. Either one will work either way.
ROAR
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Philadelphia has both types of third rail. The Market-Frankford subway-el uses underruning (Metro North style) third rail, and also has wide gauge track, same as the trolleys. The Broad Street Subway, and the Norristown Hi Speed Line, use overruning (LIRR and NYC subway style) third rail and both have standard gauge track.
The above is correct. In fact, the New York Subway's B Division, ex-INDand BMT lines and their extensions, use the same standards as PATH and LIRR, and The original PRR electrification from Manhattan Transfer was also the same. On occasion PATH and subway equipment have run speed tests on the LIRR th main line. The IRT third rail is a fraction of an inch closer to the running rails, but all current IRT cars have third-rail shoes that can easily operate on both types of third rail. The design of this type of overrunning third rail, with a protective coverboard, and the shoe approaching from the side rather than above, was pioneered on the Willksbarre and Hazelton interurban line, and used fromo the start on the original IRT subway. The Chicago L uses the gravity type shoe and no protection board above the third rail, only on the side away from the running rail. This type was used on the Brooklyn-Queens and Mnahattan-Bronx elevateds. The pre-WWII BMT subway cars had shoes that could used both the father rail with protection board and the higher nearer rail. The IRT had two third rails, one on each side, on the Bronx and Queens structures used by both subway and elevated trains, the latter also used by BMT elevated trains. This is all history, since only subway-type third rail with protection boards reamains in the New York system. Before, where elevated and subway trains ran together, BMT or IRT, the side protection board for the elevated third rail had to be ommited, because it would foul the subway shoes.
The FL-9's as delivered had double-sprung shoes that worked well on both underruning and overruning third rail, provided maintenance on both shoes and third rails was near-perfect. This allowed FL-9's to run into Penn Station as well as GCT, which they did when one of the EP-5's was not available, and always two units back-to-back, both to avoid the need to turn and also for the tractive effort needed for the grades on the Hell Gate Bridge approaches. Problems developed when maintenance fell off during the PC days, and this along with other problems with the FL-9's led to their beinhg banned from Penn Station and a haze of diesel smoke in GCT that eventually permiated the Waldorf Astoria's prime restaurant. While problems were being resolved we saw a return of P-motors and Alco S-3s to changing engines at White Plains North Station again. GG-1's had already taken over Penn Station - New Haven, and the FL-9s then had underruning-only shoes. The Amtrak FL-9s were equipped with retractable overruning shoes to run into Penn Station, and the shoes are raised to be retracted out of the way for running on diesel power on Metro North tracks, true also of the replacement dual-mode diesels.
Philadelphia's Septa Market-Frankford L uses under running 3rd rail.
The Broad Street line, however, uses over running.
sandyhookkenDuring the reporter's story, he stated that this under-running third rail system is unique to Metro North. Is anyone aware of any other rail system that uses an under-running third Rail?
Reporters have agends, not facts. Under-running third rail (I think it was devised by Sprague) was used in many places, including Phila, Paris, and Hamburg.
London, of course had its own ideas (wierd!)
Bottom Line, If a reporter says it, look for the real facts elsewhere.
daveklepperThe FL-9's as delivered had double-sprung shoes that worked well on both underruning and overruning third rail, provided maintenance on both shoes and third rails was near-perfect. This allowed FL-9's to run into Penn Station as well as GCT
My understanding is that the FL9s had soes for under-running rail, but some had shoes for over-running rail, and the locomotives were not interchangable and a particular locomotive could not run into either station.
The Geinies are the same way, AMTK locomotives carry over-running shoes, while MN locomotives carry under-running shoes. The equipment is not interchangable.
AMTK shoes *do* retract however, so the equipmen can be seen in GCT, but regulations prohibit AMTK units from leading a train due to the lack of an escape hatch in the front of the locomotive.
P&W was built with underrunning third rail, but it was converted to overrunning when the Norristown line was built. P&W uses an LIRR-like cover board for protection.
The FL-9's, as delivered, had double-sprung shoes that could pick up on both types of third rail. As problems developed, these shoes were replaced by shoes that were either overruning, on possibliy only one pair during New Haven days, or underruning. This was not done all at once, and some double sprung shoes were still around in PC days.
The retractable shoes on the Amtrak FL9s and their replacements are not retractable to get to GCT, where they can be seen only in a very rare emergency and then of course on diesel power. From Spuytin Dyvil to Croton north these locomotive are on tracks with underruning third rail going to and from Penn Sta. So the retraction is essential.
Central California Traction was using the Sprague - Wilgus under-running third rail as well, energized at 1200VDC. Note that Sprague and Wilus were working on the NYC electrification into NYC...
A couple of advantages is that the contact surface is somewhat better protected against accidental contact than over-running third rail and that it is much less suscpetible to sleet.
It's a bit sobering to have two instances of third rail related passenger fatalities in recent months.
- Erik
Yes, Sprauge was involved in the development of the underrruning type of third rail, and Stillwell in the desing of protected -with protection board, overruning third rail, first used on the Wilksbarre and Hazelton, and then used on the IRT and LIRR, H&M next, then PRR and Boston, and then the BMT. Don't forget the NYCentral and New Haven began electric operation into the old Grand Central Station before compleition of Grand Central Terminal. And LIRR electrified its Atlantic Terminal Brooklyn line and the Rockaways loop and one or two other branches before running into Penn Sta.
daveklepper Yes, Sprauge was involved in the development of the underrruning type of third rail, and Stillwell in the desing of protected -with protection board, overruning third rail, first used on the Wilksbarre and Hazelton, and then used on the IRT and LIRR, H&M next, then PRR and Boston, and then the BMT. Don't forget the NYCentral and New Haven began electric operation into the old Grand Central Station before compleition of Grand Central Terminal. And LIRR electrified its Atlantic Terminal Brooklyn line and the Rockaways loop and one or two other branches before running into Penn Sta.
Dave, you've twice mentioned Wilkes-Barre and Hazleton as an interurban line, but I think that you really mean the Laurel Line interurban (Lackawanna & Wyoming Valley RR) that ran over the nearly 20 miles between Scranton and Wilkes-Barre until sometime in the 1950s (I rode it once not long before its end of passenger service.). L&WV had over-running 3rd rail with no protection board. This was problematic in the early years of the line when ignorant trespassers, tiring of walking, would note the extra rail at a greater height, and consider it attractive for a temporary bench. Such a situation likely never turned out well.
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