Frisco 4500 class: Bearings, Frame, and track record

Discussion in '4-8-4 Northern' started by loganistrainboy1, Feb 8, 2015.

  1. I find it interesting how little information about these locomotives is readily avaliable, given four survive and they were so well known on the Frisco.
    I have a few questions.
    Given that 4500-4502 were passenger locomotives built in 1942 I would assume that the 4500's were built with a one piece cast frame and cylinders. Can anyone confirm?
    Does anyone know if the 4500's had roller bearings on the driving axles? Most modern passenger power did even if they had friction bearing rods.
    I have heard very little about how well the 4500's did on the Frisco. I read something saying that they were "prarie engines". That is a very vague description. "Prarie engine" would likely mean they wouldn't have done well with grades. I am not familiar enough with the Frisco to know what kind of grades would have been encountered.
    Does anyone know if the crews like the 4500's and how they compared to other Frisco power?
    They did not have front end throttles and had a very high tractive effort compared to the weight on drivers which in theory would have made them slippery but I have not been able to find any stories on how they actually performed in service.
    I have also wondered why the Frisco was so partial to Baldwin but maybe thats a question for another thread.

    Any help answering these questions would be appreciated!
    Logan Schupp
  2. Karl

    Karl 2008 Engineer of the Year Supporter

    1. The 4500's had a one-peice cast frame and steam chest.
    2. The 4500's had friction bearings on the wheels and the rods.
    3. Since they were a high horsepower locomotive, they needed to be rolling above about 45 mph to produce all of their designed horsepower. Working up-hill at lower speeds, they were not as effiecient as a 4200, for example. Locomotives/5-Later Baldwin 4-8-4 DBHP.pdf
    4. Don Wirth can answer this one.
    5. They had a Factor of Adhesion of about 3.94. A FA of 4 is good, anything greater than four is better, and anything appreciably lower than 4 was slippery. For example the Bolsheviks had a FA of 3.59....they were slippery coming out of the sand house.

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    Last edited by a moderator: Feb 9, 2015
  3. Thanks for the response, clears up a lot of questions.

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