Whats the point of a derail if they dont even work??

[Trainman101]

In canton mass last year a runaway freight car cut threw a "derail" and smashed into a commmuter train. Over the years i've heard of other runaway trains/cars cutting thu derails. I guess you never here about when a derail works because it does its job and sends the car off the track. My question is what percentage of derails fail? If there not working with loaded freight cars whats the point of having it? Should they throw these derails away for a split switch or some other better design?

[CN Sparky]

I can only speak of the derails at our shop... if you try to run into the shop, you'll go off the tracks... but if a unit were to roll OUT of the shop toward the inbound tracks, it would roll over the derail. Somewhat noisily... but it doesn't derail if it's in that direction.

The derail is to protect us working in the shops... the other way, I can only assume, is if the guy moving the unit out forgot somehow to put the derail down...


Perhaps the derails you're hearing about are like ours?

[DutchRailnut]

The Canton incident is still unresolved, was the derail applied ??? was derail applied the right way, was handbrake set etc etc etc.
There are plenty of instants where derails are installed wrong or on wrong rail.

[litz]

If you do some careful googling, the standard "slider" style derail we're probably all familiar with has been shown to have an achilles heel : fast moving equipment can literally bump right over the derail (and not derail).

There's a newer style derail, called a "crowder" derail, which is more effective for higher speeds.

For an example, see here : http://www.wch.com/derails.htm

And, of course, a turnout style derail is almost guaranteed to be effective.

(I think I remember seeing a shot on railpictures.net, of a pair of locomotives that went through a turnout-style derail ... both of 'em were laying on their sides in a parking lot -- very effectively derailed)

- litz

[HoggerKen]

In the few cases I have seen, the flop-over mounted derail works well in low speed situations. The Branch line was almost exclusively of this type. After the branch was rebuilt with CWR, the resulting 49 MPH speeds made those derails useless.

A MoW person left a switch open at a small elevator. Lite power came around a curve into the siding, and blew the derail into the weeds. Had it been effective, the locomotives would have ended up burried inside the elevator.

The standard now a days is the Derail/Crowder combo, or switch style derail, both sure to put you on the ground.

[Gadfly]

A very effective derail is simply a "switch to nowhere". A yard track, or siding simply has a frog, switchstand and a set of rails that are cut off a short distance from the turnout. When a cut of cars is set in that track, they simply line that switch (or another at the other end if needed) so that if there is a situation where
a runaway could occur, it is highly unlikely that the cut can "jump" a lined switch. The cars simply go into that "siding" and go on the ground. Now, granted, that can be a messy situation but can also better than the alternative (runaway). There's a few on NS in the town where I live.

Gadfly

[DutchRailnut]

In sidings however the FRA would like protection from cars rolling out but if possible also protect those working in or around such cars from accidental inbound equipment.
Such a run out switch would not work and would certainly be to expensive to add to each and every siding in USA.

[HoggerKen]

In sidings however the FRA would like protection from cars rolling out but if possible also protect those working in or around such cars from accidental inbound equipment.
Such a run out switch would not work and would certainly be to expensive to add to each and every siding in USA.

In dark territory, you must have them if the speed is over restricted. When the branch was rebuilt in 1999, switch type derails were added to all sidings for the entire 108 miles. Only within yard limits were Derail/Crowder types installed. We still have a few tracks in town that do not have derails, because obviously, no run away car or cars could ever make it to the main line. The law of physics are a good thing.

[DutchRailnut]

Must be local thing, we got switches in 50 mph MBS territory with no runout or derail

[HoggerKen]

Must be local thing, we got switches in 50 mph MBS territory with no runout or derail

It is a system wide standard, not a local thing. TWC is used to regulate traffic in dark (non-signaled) territory, thus, the need to protect from cars fouling the main line. If a signal system is in place such as ATC or ABS, it would protect against cars fouling the main line, negating the need for derails. While it sounds like you are running on track below class 7, 8, or 9, there should still be protection, something that MBS as I understand it, would not provide.

Even tracks on the CTA have derails which stop motormen from entering track they are not permitted.

[RedLantern]

Although it would be more pricey to build, I've always thought they could build something similar to the "speed retarders" used in automatic hump yards. These grip both sides of the wheels (the wheel itself, not the flange) to slow the car down. They could forge rails with a flange on the outside (or bolt one on to existing rail) and one rail would be un-spiked for a few ties but held in place by a rod to a switch stand. When the switch stand is thrown, the rail on one side would be flexed inward, narrowing the gauge, but the flange on the rail would pinch the sides of the wheels so the car would still slow to a stop even if the flanges ran up onto the rails. In this case, the car stops, the wheelset might get damaged, but not the trucks or the car, (or more importantly, the load), and cleaning up the mess would be as easy as throwing a switch stand.

[NV290]

Derails work fine.

The Coheno lumber incident was caused by a car rolling over a derail. It is actually not that uncommon with older derails like the one there. The derail at Coheno was connected to a circuit controller as most industry derails are in signal territory. This insures that if a crew forgets to put a derail back on, the signals protecting that block will display stop signals.

Old "block" style derails were made of cast steel and were designed to derail cars that were much lighter then cars of today. Most older derails were also built as "doubl ended" derails in that they were designed to derail cars on both directions. Protecting the mainline from cars rolling out and protecting the industry from cars coming in. These earlier designs were effective on the lighters cars. But many of todays cars are so heavy that older derails are not up to task. Depending on the speed, cars can roll over them, as was the case with Coheno or can simply cut them in half or knock them out of place is the ties and/or spikes are in bad shape.

Modern derails are made of fabricated steel and are not only much stronger, but they are much better engineered to derail the heaviest of freights cars. And they work very well when properly installed. Most manufacturers now require the derails to be lag bolted into place to make certain that a car will not knock them out of the way. And while double ended derails are still made, manufacturers reccomend that a single ended derail be used where possible since they are more effective. They even make super heavy dity derails now designed for locomotives. Where speed is an issue, a device known as a Wheel Crowder is used to insure the car wheels ride onto the derail and then off the rail. I have seen a 130 ton loaded coal car get shoved over a derail at almost 14 MPH and it went right on the ground without hesitation.

But the only 100% guarantee of derailing a car is the switch point derail. These are VERY expensive since they utilize a switchpoint, switch stand and specialized track components. But the advantage is they will derail anything at any speed. The MBTA has since installed one at Coheno as well as at any location on thier tracks where the industry tracks are uphill from the mainline. This will prevent any future incidents. They also made inspections of all customer derails to make sure all are in working order, properly secured and functioning.

[HoggerKen]

FRA track standards require that derails installed are both adequate to the application, and inspected and maintained. All the old cast type derails we had are gone now, in favor of the Crowder type or switch type. The switch type is only $150,000 installed.

[NV290]

FRA track standards require that derails installed are both adequate to the application, and inspected and maintained. All the old cast type derails we had are gone now, in favor of the Crowder type or switch type. The switch type is only $150,000 installed.

Where i work alone, there are still dozens of cast derails and place and i know of. And i know of ONE Wheel Crowder.

[HoggerKen]

In the last four years, four cowder, and six switch types have been installed in town. Two cast derails still exist on industrial spurs. On the 108 mile branch it is an even mix of crowders and switch types. Any cast types are on spurs no longer in service, or seasonally used. This includes 3 ethanol plants, four grain elevators, one Bean plant, three fertilizer plants, and seven odd industries. In town, the ethanol plant converted the switch type derail to a normal switch for a headroom spur for their 400 car yard. Neither of the three industrial spurs in town have derails,and the yard is protected by a derail on one of the two new passes. The locomotive service tracks, and RIP tracks are only protected by blue flags. Modernization of a dark territory sure makes things a lot safer.