Spring Frog on turnout

Whie watching a video of speeders they went through a switch that had a spring frog on it. They were going slowly and I could barely see a moving part on the frog. Whats it used for and why? Is this a new invention and how rare is it on the RR's?

Spring Switches are not a rare thing. You'll find them being used in Yards and branch lines where traffic is heavy. A switch crew may have a section of yard tracks directley connected to a main trackheld up for a few hours. The switch can be left open for switching allowing trains to pass by oposed the open switch while it is open one the train clears the switch crew can pull back on the main with out haveing to rethrow the switch.

Spring switches were used on main lines too. The NYS&W had one at the end of their double track in Riverside (Paterson) NJ that was in use until they took the second track out of service in the late 60's-early 70's.

Spring switches are pretty common ... but wasn't the question about spring frogs (not points)?

Movable frogs are interesting. I can't imagine one being sprung unless it was part of a spring switch.
The lines I'm familiar with don't use movable frogs so I have no first hand knowledge.

There is a frog known as spring or sprung.they kinda fell out of favor in the 60's-70's
although I understand they are making a come back now.
they were used on heavy duty main lines where a seldom used spur or siding was located.
springs kept the flange way closed for the main route providing a smooth ride
and less wear at the frog.

try this photo on the PRR Elmira branch.
charles


http://www.flickr.com/photos/45085819@N02/4481553138/

RSD15 wrote:try this photo on the PRR Elmira branch.
http://www.flickr.com/photos/45085819@N02/4481553138/

Interesting. What causes the frog to open when a facing train takes the diverging route?

RSD15 wrote:There is a frog known as spring or sprung.they kinda fell out of favor in the 60's-70's
although I understand they are making a come back now.
they were used on heavy duty main lines where a seldom used spur or siding was located.
springs kept the flange way closed for the main route providing a smooth ride
and less wear at the frog.

try this photo on the PRR Elmira branch.
charles


http://www.flickr.com/photos/45085819@N02/4481553138/

cool can't say that I have seen that before but might have. If anything I more than likley never paid much attention to them.

The LIRR has a few around Hillside, now.

Amtrak has installed some on the NEC in NJ, most notably, as part of County Interlocking, at the switch from track 4 to the Millstone Branch.

All? of the dozens of main line turnouts on the SP Peninsula between San Francisco and Santa Clara are spring-frog (except within 4th St interlocking limits at SF). The new UP x-overs on Donner Pass (to allow stack trains to run wrong main to avoid tunnels) are spring-frog; maybe they're usual on new installations on UP now?

Do these frogs come equipped with a grease lubricator, are they manually greased, or no grease at all ? I would think that a fast moving train, such as on the NEC, would throw one heck of a spark, flange to restrainging rail, going through one of those. (Or even worse- cause a derailment due to the frog sticking, when it would essentially become a "derail" device.)

3rdrail wrote:I would think that a fast moving train, such as on the NEC, would throw one heck of a spark, flange to restrainging rail, going through one of those.

Depends what you mean by "going through". No reason anything untoward would happen when running thru it straightrail?

On the SP, trains are allowed 50 mph diverging thru the springfrog #20 turnouts, but none of those on the NEC, are there?

justalurker66 wrote:

RSD15 wrote:try this photo on the PRR Elmira branch.
http://www.flickr.com/photos/45085819@N02/4481553138/

Interesting. What causes the frog to open when a facing train takes the diverging route?

It sort of looks like a diverging train would just roll over the frog without opening it at all (or inconsistently, since it would be levered a bit by wheel flanges), and be restrained from derailing by the third rail opposite the spring frog. Can't imagine it would be good for the unsprung point of the frog or the flanges of diverging cars, but at slow speeds that wouldn't be too terrible.

It's possible that new ones have a remote lever to push the spring open, but I haven't looked for any like that.

mtuandrew wrote:It sort of looks like a diverging train would just roll over the frog without opening it at all

Usually? Always? the straight-route trains are the ones that roll over it without opening it.

timz wrote:

mtuandrew wrote:It sort of looks like a diverging train would just roll over the frog without opening it at all

Usually? Always? the straight-route trains are the ones that roll over it without opening it.

I realize that - when looking at the picture linked earlier in the thread, the left-most safety rail would keep wayward wheel flanges on the straight track from picking the frog. I'm talking about diverging-route trains though, and questioning whether a diverging wheel flange would be able to push the spring switch aside. It looks like the sprung section is bolted solidly to the right-hand straight running rail, which would inhibit its ability to swing open far enough for a flange not to bump over the junction. This may be an illusion, and if there's a degree of freedom this wouldn't be an issue. Also, it doesn't appear that it would be a problem opening the spring when entering the straight track from the siding, as a flange would have much more leverage further down the sprung rail.