I’m a little confused at the picture on page 19 of the current issue of Trains magazine. As a railfan, I’ve seen lots of turnouts but I can’t quite fiqure this one out. Is this a “swingnose” switch or am I missing the obvious? How does the wheelflange pass through the mainline rail?
It doesn’t–it actually goes over the rail, being held in alignment by the guard rail on the opposite side and the elevated areas of this frog. Trains using this route are traveling at lower speeds anyway, so this isn’t too jarring for them (never heard of it being done with a switch, but know about crossing diamonds done similarly). Meanwhile, trains on the main line have an uninterrupted rail at the frog, which reduces the expense and time loss of frog replacement.
I think you were referring to a moveable-point frog, which closes the gap in the rails for the route being used. This would be a good solution for a switch that has two high-speed routes and a frog angle that might otherwise make them derailment-prone.
A guy here with his feet firmly on the ground (Mudchicken, for example) might be able to do a better job of explaining these switches.
Carl/CShaveRR said it as well as it can be said. A flange bearing frog (sheep jump) becomes into play when the side track is little used or low speed. A lot cheaper than a spring frog or a swingnose frog that can handle the higher speeds, but require more attention, usually by the chronically short in supply track welder who can’t get any track time from the harried dispatcher who can’t be left alone by the micromanaging operating supervision.
First used in crossing frogs, these turnout frogs can only be used in limited places where FRA has granted an exemption (based on the design) from the frog guard and check gauge rules (the guardrails opposite these things by nature are pretty beefy to keep the wheel flange tread fom falling/sliding off the side of the polished ball of the rail)…Frogs, crossing or turnout, carbon-cast-explosive hardened-manganese-et al, take an incredible beating and the metallurgy can’t keep up with the abuse. Speed only makes the abuse worse.
(We know TRAINS Matt Van Hattem spent a good while looking at the Progressive Rail frog just inside the exhibit hall at AREMA in Salt Lake City a few weeks ago - complete with the model train switch with a UP RS-3 and 40 foot boxcar used to demonstrate something new with something terribly dated.)
Thanks for the explaination. I quess I had a hard time believing that the wheel accually went over the mainline rail.
The mechanical people are not exactly thrilled with this development either. (But then, when the inevitable rash of broken and nicked wheel flanges comes into play, the track folks can tell them to reduce the wheel loadings - or just live with it[}:)])
[(-D][(-D]
…Not having my new issue of TRAINS yet…Are you saying the wheel actually passes over the rail…If so, is it the flange that actually takes the load as it passes over…
And doesn’t this present such a “hump” in the rail system so as to cause concern…? Could a rigid frame steam engine pass over such an arrangement…?
Guess I’ll have to wait to see a photo to really understand what’s going on with something like being described. Have never heard of such of an arrangement.
…Finally, now have my new current issue of TRAINS, and on page 19…I must admit I have no idea how a wheel passes over that continous rail at that turnout. And If I could, can’t see the advantage of doing it in such a way.
Modelcar, & others -
Search on the Internet for “flange bearing frog”, and roam extensively through the results (I used Google’s “Advanced Search”). There’s a lot of text out there, but if you get or have a sense where to look (don’t want to promote another forum here, that wouldn’t be right) you’ll find a few photos, some diagrams, and a lot of pretty detailed explanations, plus lots of other links and references to more of same. But a clear diagram would be a big help to comprehending this for people without M-O-W experience, that I’ll concede, and those are scarce.
Good luck, and have fun !
- Paul North.
…Thank you Paul, we’ll do a bit of checking. Sure a strange piece of RR infrastructure. Have never even heard of it before.
Greetings,
Thank God somebody finally posted about that photo. I must have sat and looked at that same picture for hours trying to make sense of what I was seeing. Couldn’t get my head around the obvious conclusion that the wheel had to jump the rail.
Gregory
I’ve noticed one of these turnouts in my town. It’s been there quite a while. I’ve never watched as a train passed over it but after some thought I think it might work just fine. Rather than being a big hump that would make a railcar tip or lean, I think because of the short ramp up and over that each axle would “toggle” or climb over the rail one at a time. I would bet that the railcars don’t even lean as they pass over at slow speeds.
Has anybody seen one in action?
Hi All
I was looking at pictures of these structures online (sourced by Paul North) and have two questions of the track/rail experts. I notice that the head of the high speed rail is nicked significantly where the flange of the lower speed wheel impacts the railhead. 1. Wouldn’t this type of ‘abrasion’ or ‘cutting action’ (if that’s what it is) significantly damage (cracking vertically, peeling horizontally) the higher speed railhead (and even the h/s rail web and base) as the flange impacts over time continuously impact the h/s railhead thus causing it to deteriorate more quckly than under normal usage. 2. Wouldn’t this damage occur no matter what the speed and frequency of the lower speed trains, given that the h/s railhead is ‘getting beaten up’ in both directions (ie transverse and longitudinal). By the look of the diamond’s construction it would be a heck of a thing to replace, or are these diamonds track panels that could be changed out fairly quickly.
What’s the verdict on their use in practice?
Charlie
Chilliwack, BC
…I continue to wonder what’s the economy in them…?
And are both rails raised to the elevation of the low speed rail that allows the wheel {flange}, to passe over the High speed rail…? If not, wouldn’t it flounder the cars side to side…This is so unusual I believe it has many of us spooked. And all for what…?? As I wondered above, why do it…?
When I saw this switch in TRAINS, I was immediately reminded of the 'Wharten Safety Switch.
At one time, the C&A advertised its use on their line to let passengers know how safe their rairoad was. I found the advertisement in only one old copy of the Official Guide, so I suspect it was not as good as it sounded. It sure wasn’t in use when I started to work (1947) for its new owner, the GM&O.
The Internet site below describes it rather well but the illustration doesn’t remove all doubts.
http://mysite.du.edu/~jcalvert/railway/wharton.htm
(edited by selector…just press “enter” immediately after pasting, and it will become active)
It obviously provides a good route for the main (straight through) line, but many main lines were single track affairs that needed passing sidings.
Art
As a start to understanding this better with a closely related item, see the Light Rail Track Design Handbook, Chapter 6 - Special Trackwork, the text at 6.6.3 - Flange-Bearing Frogs through 6.6.5 - Lift Over (“Jump”) Frogs, on pages 6-31 through 6-33 (71 through 73 of 79 in the “PDF” version below), and the depiction of same in Figure 6.6.5. - Lift Over Frog Design - NO. 8 TURNOUT FROG - LIFT OVER DESIGN - RIGHT HAND (SHOWN) and especially A - SECTION ALONG LIFTOVER FROG FLANGEWAY on page 6-34 (74 of 79 in the “PDF” version below) at:
http://onlinepubs.trb.org/Onlinepubs/tcrp/tcrp_rpt_57-c.pdf
- Paul North.
Paul
Thank you for the information provided. It appears from the detail given in 6-31 through 6-33 that it is critical for the lift flange to be carefully designed (for speed and weight requirements) and maintained (pretty carefully) in order to operate effectively, given the wearing of the lift flanges and guard rails in regular service. I can see where they could be a problem for MOW people. BTW they appear to be a recent development given that the published standards seem to date from 1988. Were they intended to be a low-cost ‘fix’ although I would have thought they aren’t a lot different in cost from a conventional diamond.
And that’s only from the track point of view…then there’s the flanges…
They sound pretty ‘iffy’ to my unexpert mind.
Charlie
Chilliwack, BC
On a similar subject, when insulated frogs came into play on mainline railroads, some locomotives would literally have to do a “leapfrog” due to their wheel size. Of course, I am talking about geared locomotives.
The best example of this can be seen on a video that’s about Mount Emily Shay #1 out in Prineville, WA. When they were built, they made their wheels about twice as wide, in order to run on slightly out-of-gauge track easily.
The only cases where this would happen is where a geared locomotive would have to go onto a mainline railroad for some reason. In the case of Shay #1, it was out at Railfair in CA, and not all of the switch frogs were non-insulated. So, it was quite comical to watch the trucks bounce over the frogs.
This summer when the Cass Scenic Railroad Shay 6 went to Elkins (67 miles), there were a few frogs that the West Virginia Central Railroad had to replace.
Ahh, technology (and all of it’s strange faults)
Phil
Phil -
I’m not familiar with “insulated frog” in the prototype railroad world - only in the model context. Do you mean “self-guarded” or “self-guarding” frogs instead - the kind with the high “wings” on each side, so that no guard rail is needed on the opposite (“turnout”) rail to keep the wheel flanges on the proper route through the frog ?
For an example, see the photo at the middle of the right-hand column on page 30 of the Industrial Track Inspection Guide at:
http://canteenbooks.com/Industrial_Track_Inspection_Guide.htm
(Somewhat surprisingly, that was the best one I could find quickly.)
That makes more sense from the standpoint of causing wide wheels to jump. It seems they are also a problem for the track car / motor car operators - see this page from NARCOA (North American Railcar Operators Association):
http://www.narcoa.org/info/safety/guard_frogs.htm
- Paul North.