[PRCo] Ramped__Frogs-__-Mates

[Jim Holland]

Bob Dietrich wrote:
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> Fred and Jim, your explanations are very good, but they raise a 
> question in my mind.       You both say that the right wheel must ride 
> on the flange in the flangeway.       I was under the impression that 
> the tread spanned the gap between the rail and the point, much like a 
> standard railroad frog.       If the flange rode on the casting it 
> would quickly wear a grove in the casting and cause some nasty bumping 
> and deterioration.
>
> Am I misinformed on this?       Is the flange-way plus the width of 
> the point in the right-wheel casting really wider than the wheel 
> tread?       I know models span that gap but model wheels tend to be 
> wider than prototype - but then so do clearances.
>
> Bob .

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Very  Standard  Practice  on Street Railways for the flange to ride in 
the gutter through frogs and through mates.       Once grooves are worn 
into the gutter then the wheel is riding on the railhead but the ride is 
far smoother with greatly reduced chance for chipping the tire.       If 
the turnout is used in primarily only one direction then the wear is in 
that direction.       Pittsburgh would send out the welder to fill the 
frogs with welding rod  --  That  Is   A-L-L   the welder did   ---   it 
left Multiples of Hills, Valleys, Peaks, indentures, etc. etc. etc. and 
was  Extremely Rough to Navigate and Horriffically Noisy until worn in  
--  probably chipped the flanges!!!
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The Primary Reason for riding on the flanges is to prevent chipping the 
tire  --  every other reason is secondary.       Passing through 
90-degree frogs is most problematic for chipping as the whole wheel at 
the same time Theoretically Bangs across the gutter;  with so many such 
crossings on a TrolleyCar system the propensity for chipping tires would 
be Extremely High thus all frogs and mates were Built with a gentle rise 
in the gutter through the gap.       The problem of chipping is greatly 
reduced as the angle of the frog drops below the 90 figger and is much 
less problematic with a mate.
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I have mentioned right here before that Each Truck on a TrolleyCar acts 
like a 4-wheel rubber tired vehicle when rounding a turn  --  the back 
axle does Not want to follow the path of the front axle;  the rear axle 
of a truck tries to follow inside the circle circumscribed by the front 
axle but on a trolleycar, the rails restrain but also Record this 
action.       There are obviously other forces which come into play on a 
railcar but the principle is still the same.       The turn into the 
42-Dormont wye was used by Multiples of Trolleycars all day and the 
straight through direction for the 42/38 owl was used only hourly and 
only 5 times a day.         There were Dual Grooves in the Mate of the 
turn on the Straight Through Rail  HEAD  (so obviously the grooves in 
the gutter were well worn as well!!!)  with the outside groove for the 
wheel on the front axle and the inside groove for the wheel on the rear 
axle Of  Each Truck!!!       We had such a situation here in SF as well 
that caused a Derailment  --  grooves in the railhead were so deep in 
the mate that it acted like a Self-Guarding Mate  --  resulted in split 
switch with front truck going the correct way and back truck taking the 
other direction which means that the rear truck climbed up and over the 
point!!
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Railheads in simple turns at intersections  (without turnouts and 
without frogs and crossings)  reflect the same  --  dual grooves in the 
railhead.       Within the last decade it was so pronounced on several 
curves on the Judah line  (where I live)  that the rail had to be 
replaced, thus giving about 25-years life to the rail that PCCs and 
older cars had used for 50-years without replacement!!!!!!!
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Trolley Wire frogs do the same  --  Ramp Down so that the wheel / shoe 
is riding on its flanges rather than bumping across the gap to allow the 
flange to pass.       Without the ramping the dewirement quotient would 
be severely high  (ramping needed much more for Wheels than for 
Shoes!!!!!!!)       And thus frogs can wear in one direction as well and 
here we see the example at the 42-Dormont wye  --  Again!!!!!!!       
Only 5 trips straight through so the points in the overhead frog were 
almost closed toward the diverge move into the wye.       One summer 
night the owl went through and dewired  --  I could hear it at my house 
and see the arcing as the pole struck the wire.        Next morning when 
I went up to the wye there was a new overhead frog!!!!!!!
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http://lists.dementia.org/files/pittsburgh-railways/RR%20Double%20Point%20Turnout%20096.jpg
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http://lists.dementia.org/files/pittsburgh-railways/03-Tylerdale%200096%20195xxxxx%20RSchramm.jpg
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http://lists.dementia.org/files/pittsburgh-railways/03-Track%20Drake%20Loop%20Construct%201953xxxx%2001.jpg
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http://lists.dementia.org/files/pittsburgh-railways/Smithfield%206th%20Aerial%201951xxxx.jpeg
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Jim___Holland