| Posted by J Moller on October 15, 2025 | |
Thank you for sharing these many Baldwin images over the years.
While one might scoff at this single unit, unlike several ill-fated coal-gas turbine locomotives tested by C&O, UP, etc., this Class S2 locomotive showed promise. Using familiar locomotive technologies for the tender and boiler, it used turbines found on ships. On this side we can see the larger forward-driving turbine as well as smaller driving wheels balanced for geared rather than reciprocating motion and able to roll at passenger train speeds. On the other side was located the smaller reversing turbine. The locomotive ran reasonably well generating good power and fuel economy at higher speeds but not so much at lower speeds. Operating until the early 1950's, it and the famous T1's were soon eclipsed by the more reliable and economical E7 units. The following website has a lot of interesting information including the turbine gearing and numerous links. https://en.wikipedia.org/wiki/Pennsylvania_Railroad_class_S2#Design_specification
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| Posted by Carl Kulzer on October 15, 2025 | |
Thank you for this great shot. It is too bad it was a failure. I had a Lionel steam turbine,and years later a O scale Sunset Models version of it.
Thanks for the memories.
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| Posted by mmi16 on October 15, 2025 | |
Amazing how much 'tractive weight' is removed from the drivers with the 6 wheel leading and trailing trucks.
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| Posted by Jeff Sell on October 18, 2025 | |
Nice photo and thanks for sharing. She was a nice looking machine and she also has the typical Pennsy features like a Belpaire firebox along with the classic PRR front end look. I wonder how the tractive force was calculated? Two of the variables in the typical tractive force equation uses the diameter of the piston and the length of the stroke of the piston. The S-2 had neither of these features because it was a steam turbine. Must have been some other rocket science tractive force calculation.
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| Posted by J Moller on October 21, 2025 | |
There is not a whole lot of data on the internet, but the following suggests the locomotive could have handled GG1-sized trains at speed:
"During a test run officially arranged by PRR on 30 March 1945, S2 #6200 towing a dynamometer car was able to pull a 17-car train over a distance of 48 kilometers (level track) at a speed of 110 mph (180 km/h) between Fort Wayne and Chicago. Engineer Mr. Flaya Cartwright and Fireman Mr. M.E. Brown were assigned to this official test run. E.S. Cox, a British locomotive engineer, once traveled on the footplate and reported that "100mph was maintained and exceeded for 12 consecutive minutes". While economical at speed, the locomotive was highly uneconomical at lower speed. The turbine used less steam than conventional locomotives above 30 mph (48 km/h), but below that the locomotive used too much steam and fuel. The boiler normally operated at 310 psi (2.1 MPa), but at low speed the pressure could drop as low as 85 psi (0.59 MPa). The increased fuel usage at low speeds caused the firebox to run hotter, which sometimes caused stay bolts to break."
Source: https://locomotive.fandom.com/wiki/Pennsylvania_No._6200
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| Posted by Erick Anderson on October 29, 2025 | |
The locomotive was supposed to be a 4-8-4, but lighter steels were unavailable because they were needed for the war effort. The greater weight required additional axles at the front and back.
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