It became standard for high capacity cars, such as grain and coal, to be
equipped with 36" wheels. The 36" has given way to 38" in recent times. The
larger wheel was seen as a "fix" to the shelling problem which currently
represents the single biggest cost of car repair.
When one considers the work that a wheel must do it is easy to understand the
high cost of doing business. Besides "merely" supporting the weight of the car
it must guide the car and, at the same time, absorb the mechanical shocks
associated with operation over tracks of widely varying quality. Vertical and
lateral moments create high levels of energy transfer within the wheel. So much
for support and guidance. Also listed among the duties of a wheel is the one
related to STOPPING the vehicle. As much as 40 horsepower worth of braking
energy may be applied to each wheel on a car. The by-product of this energy is,
of course, heat, LOTS of heat. The greater the "length" of the wheel tread
(increased wheel diameter) the more area is provided for dissipating the
braking heat which is generated every time the automatic air brakes are used by
the Engineer.
Also of potential interest to "wheel fans" is the CURVED PLATE wheel design
introduced many years ago. The "PLATE" is that part of the wheel extending from
the hub to the tread. In early designs it was "straight" and resisted lateral
deflection. This resistance resulted in a substantial number of plate failures
which lead directly to complete wheel failures. I believe we all understand the
ramifications of a wheel failure. The "CURVED PLATE" allows a certain degree of
flexibility during high stress moments of the wheel in both lateral and
perpendicular (to the axle) planes and, thereby, drastically reduces plate
failures. Use 36" wheels under all of your high cap. bulk commodity cars.
Does this help John?
Karl
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----- Original Message -----
From: JOHN J. OLSON & DEBBIE NIESS
To: BRHS
Sent: Sunday, October 29, 2000 8:44 AM
Subject: [BRHSlist] Wheel size on Hoppers
BRHS Members,
I have a stupid question that I have been trying to find an answer for.
Did the CB&Q 100 Ton Quad Hoppers, like the ones Walthers made in a single &
6 pack, ride on 36" wheels or 33". I have looked at photos in the Morning
Sun Color Guide to Frt & Pass Equip and can't tell for sure although they
look like 36". I know 36" wheels are the rule for most 100 Ton coal and
grain cars but was that the rule back in the 60's as well? I just want to be
sure. The 'Burlington Bulletin' on Hoppers doesn't say- or I just overlooked
it. Thanks,
John Olson
Jim's Junction
Billings, Mt.
<http://www.jimsjunction.com>
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