Hauling a trailer was hard on an RDC, as noted above. Budd’s warranty would be voided by hauling a trailer (Budd got tired of replacing transmissions?) because of the HP/ton ratio designed solely for powering the car, unlike earlier railcars. Some railroads used two RDCs in an attempt to get around this, which may have been accepted.
After WWII GM came up with a very nice combination for a power train that consisted of the 6-71 GM diesel coupled to a torque converter and, if needed, Allison automatic transmission. They were used all over the place in the late 40’s and 50’s. The early ones with the blown engines were good for about 150 HP each. I don’t recall if the RDC has a transmission or just a reversing gear, but two of these, with the I-6 diesels laid flat under the floor, powered the RDC’s.
I’m guessing this combination was cheaper than the low power DC diesel electric gear available back in the day.
Not hardly. The engines in RDCs are 6-110s, not 6-71s – a very considerable difference. These engines make considerably more than 150hp each (nominal commonly given as 275hp each for 2-motored cars). IIRC they have centrifugal superchargers, not those infamous ‘screaming’ Roots blowers. The ‘standard’ transmission is a 2-speed planetary design, with low speed being via the torque converter and high being direct drive – I do not know how different the arrangement in the ‘hot rod’ high-speed cars or proposed trains might be (other than taller gearing), but since three of the Roger Williams cars survive it ought to be possible to find out.
If I remember correctly, MARC did try repowering with 6-71s in the late '70s, unsuccessfully. (I believe very unsuccessfully…)
Yes!
and
Yes!
Game over.
When diesel-electrics were first introduced, they were based on very conservative technology. For example, the Alco-GE S-1 through S-4 series, designed in the late 1930’s, had four (4) 250hp 600vdc motors under them, the exact same traction motor housing as was on the 1927 Lackawana 3000vdc motor cars. The motors were wound for 3000vdc as opposed to 600vdc but those motor cars were 1000hp (4x250hp). Even some of the control equipment were duplicate between them. I know because Hobo purchased the motor cars as their rolling stock and stripped them. The B&M “sacred Cow” 1140 had a three-axle power truck that would have used three traction motors (3x250hp) to take the output of the 800hp diesel generator. The B&M BL-2 1551 had a “transition” meter (read ammeter) for its 1350hp generating plant because at max output (stalled) it would burn out the traction motors in about 30seconds. Today the typical traction motor puts out 750hp. To properly utilize these high hp traction motors you have to have high wheel loadings since all tractive effort is based on the coefficient of friction (approx. 0.25) for steel wheel on steel rail) The problem was the under-the-floor power plant was getting high enough output in the space available. But even the old gasoline-electric railcars with the motor-generator transverse in the cab could pull a specially- designed light single trailer and the Lackawana motor cars all had a trailer fleet. When the Branford Trolley Museum was powered by an ex-NYNH&H S-1 diesel generator, there was a mid-west 1000hp high-speed car that would routinely trip the breaker if put above the first notch.
Now if you put a couple of jet engines on top of an RDC you should be able to go almost 200 MPH, without a trailer of course.
Paul
A NYC fan
The problem with this Forum is that I keep learning things I didn’t know I wanted to know . . . [swg]
“How Torque Converters Work” (multiple short pages):
http://auto.howstuffworks.com/auto-parts/towing/towing-capacity/information/torque-converter.htm
“How Torque Converters Work! (Animation)” (4:24 long):
http://www.youtube.com/watch?v=z5G2zQ_3xTc
- Paul North.
Been a member of BERA (Branford, Shore Line Trolley Musuem) since 1957. I think my memory tells me the diesel came from the B&M, not the NYNH&H. The two cars that could be depended upon to trip the breaker were the ex-CRANDIC-ex-Indiana high-speed and North Shore 709.
A diesel electric RDC would have cost about 40% more than the diesel-mechanical one provided. However, today, with the wheel-motor concept, probably everything could be under-floor. But then. no.
TheRoger Williams “Budd Hot Rods” only ran into GCT the first few years of their lives. Even before Amtrak they were booted off the main line and may have lost their third-rail powering ability. Amtrak put the complete set together for their New Haven - Springfield - Boston service, connecting with NEC trains at New Haven. Rode it.