Covered Wagon Question

[Murphy Siding]

Why? Why were the first successful diesel locomotives built with car body construction (truss girder type construction, with body panels over the structural framework) ? Were'nt steam locomotives of the time built more like a road switcher ( big, solid bottom frame, with everything else bolted onto the top ) ? Why the difference from the familiar, and why did it take 15 years to catch on to the road switcher type of frame again? Any thoughts?

[dehusman]

The first road diesels were primarly for passenger trains so were "streamlined" to match with the passenger trains. It also allowed a mechanic to tweak the machinery enroute.

Switch engines were the first "hood" units and were designed for improved visibility. As road diesels were designed to function as either a road or switch engine (RS1) they adopted the hood design.

Dave H.

[Murphy Siding]

Dave- your comment about streamlining makes sense. I guess I'm thinking along the lines of : If the average locomotive of the time was built on top of a great big, solid frame, why did the designers come up with such a departure as the bridge type girder construction? Wouldn't a logical evolution have been to build a cowl type diesel unit? Those first switchers, like SW-1's,etc., were built built on a frame. To jump from the SW-1 to the E unit or the FT, they had to at some point say "hey! let's make this different".

[mudchicken]

(1) They started with E-Units on cast frames. Remember the span on an E unit? (and the fuel did not tag along behind in another car).....

(2) The track structure was much lighter in the 1930's...90# and 110# rail was the big stuff.

(3) The internal truss was lighter and inherently safer and helped lower the center of gravity. Everyone forgets that the EA's (EMC 511 & 512, B&O 50 & 51, ATSF 1 & 2 alias Amos and Andy) followed in the footsteps of the enclosed motorcar doodlebugs and also that those bulldog noses were designed to fail BEHIND the cab to protect the crews.

(4) Pullman's underpowered 1933 "Railplane" whetted the imagination of ATSF, CB&Q, UP and others for streamlining.

[Wdlgln005]

You may have to go to chicago and the MSI when the Zephyr reopens. Seems to me, the diesel engines of the time were a lot smaller- only 6-8 cyl. It must have been a big deal to put 2 motors under the hood to get 2000 hp in one carbody. Take a good look at the Baldwin centercabs. Even the GG1 was new at the time.

Perhaps the most important item yet to be produced was the ability to MU several engines together. Even with a 4 unit FT, there was a great debate to call that 1 large engine to match the HP of a Big Boy.

[DSchmitt]

The diesel engines of were less reliable and needed more maintenance than latter engines. Many early diesel powered trains had a mechanic in the crew. He could perform running repairs and maintenance in an enclosed, all be it tight, space. No danger of falling off the loco while working.

[daveklepper]

The first diesels were the early box cabs built with the experience of the electric locomotives that they resembled. Then came the real switchers, with hoods on frames, designed for visibility. Then came the passenger diesels, which were sold as part of a streamlined train, whether or not they were articulated, and the E and TA carbodiesm plus the Alcoe DL-10_ carbody, were designed to blend with the streamlined trains they pulled.

[dehusman]

The FT wasn't called 1 engine "to match the hp of a Big Boy", the early diesels were semi-permanently coupled and numbered together because of union rules. The Railroads were afraid that if they numbered the engines separately, the unions would require an engine crew on each individual engine in the consist.

Dave H.

[garr]

For a great in-depth read about this and a lot of other details about diesel developement, read "The Dilworth Story" by Franklin Reck. It has been a while since I read this book so I can't give you a definitive answer, but this biography about Richard Dilworth is worth the time you will spend reading it.

As daveklepper states above the evolution of diesels started with boxcabs. However, before diesels, there were gas-electric railcars that GE was developing in 1910 and later distillate powered engines. Most of this developement was done for passenger operations as the horsepower was not there for freight demands. This evolution continued on in the passenger realm more so than the freight. So the obvious flow of developement was a diesel for passenger service thus the carbody design.

Dilworth had no formal engineer schooling and only spent one-half day in any formal schooling of any kind. He learned on a need-to-know basis. His skills learned during a patchwork of jobs in his youth made him the right man at the right time for locomotive developement.

Check used book stores on the web to find a copy. Usually in the $15 range.

Jay

[dldance]

Early diesels drew as much on the heritage of passenger cars. The early power trucks were modifications on the heavy weight passenger trucks of the time (both 2 and 3 axle). And the "running mechanic" on board was really needed. The engine quit on the UP Streamliner during an early cross country demonstration run and won't restart. Bascially, the on board mechanic "hotwired" past the failed relay and restarted the motor as the train was coasting to a stop. The fix worked, the motor restarted, and the streamliner had a successful trip.

dd

[jchnhtfd]

The mechanical problems in the early diesels were one of the reasons that the twin-engine versions, like the EMD E units, were as successful as they were. They could, and rather frequently did, run quite well on one engine while the other was worked on. But you could only do that on a cab unit, not a hood (unless you had a serious death wish!).

[Murphy Siding]

garr: Thanks for the info on a book about *** Dilworth! I'm going to start looking right now.

[martin.knoepfel]

What did they do when they had to shut down one diesel-engine on a twin-engine locomotive? Did one truck just trail until "its" diesel-engine was restarted or did the other engine supply electricity to all motors?

[adrianspeeder]

I think so. Thats how the little GE centercabs are set up.

Adrianspeeder

[Randy Stahl]

The big engines, like the EMD E units were divided into 2 seperate locomotives in one carbody. If one prime mover went down you lost half of the locomotive. same story with the DD40X
Randy

[mudchicken]

QUOTE: Originally posted by Randy Stahl

The big engines, like the EMD E units were divided into 2 seperate locomotives in one carbody. If one prime mover went down you lost half of the locomotive. same story with the DD40X
Randy

Would you rather be working inside the cramped innards of an F3 or opening doors on the long hood of a GP7while moving? My impression is that there is only so much one can do on a moving locomotive behind the back wall of the cab. (Most of that being around the governor and air starter handle.)

[garr]

Murphy Siding,

Go to www.alibris.com and type in dilworth on the subject line. Info for an used copy @ $6.95 should show up.

Jay

[Randy Stahl]

QUOTE: Originally posted by mudchicken

QUOTE: Originally posted by Randy Stahl

The big engines, like the EMD E units were divided into 2 seperate locomotives in one carbody. If one prime mover went down you lost half of the locomotive. same story with the DD40X
Randy

Would you rather be working inside the cramped innards of an F3 or opening doors on the long hood of a GP7while moving? My impression is that there is only so much one can do on a moving locomotive behind the back wall of the cab. (Most of that being around the governor and air starter handle.)

Pesonally I prefer neither, at high speeds it is very difficult to keep the car body doors open on hood units. I've had more than enough pinched fingers as the doors slammed shut on me. I suppose if a covered wagon had a steam generator it would be handy to have it enclosed in a carbody since steam generators require alot of attention. On the E units the isolation switch for the rear engine and for that matter the front engine were back in the carbody so you needed to go back there anyhow just to silence the alarm bells. The F units that had roof mounted water tanks were a skull buster.
Randy

[jchnhtfd]

One thing Randy didn't note about the E units and isolation -- indeed you could shut down either engine (and the associated truck). Which turned off the alarm bells. However, if one of those bells was the wheel slip indicator, you had better be darned sure that all the wheels were turning, and that you didn't have a locked wheel set!

[Murphy Siding]

Garr- I just finished reading The Dilworth Story biography. Thank you for the recommendation. I'm still a little bewildered though. The book mentions that Dilworth designed his first diesels like a boxcar. They were to be "simple, honest, hard working machines" built with no frills. Later, they had to modify the cabs to improve some safety and visibility concerns. Isn't a boxcar built as basically a rigid frame with a metal shell on top of it? A truss girder frame had to be a real departure from the norm at the time.