I seem to remember some old GE U-boats that had 16 notches.
The C&NW E8 units had a throttle interlock which required the throttle lever be allowed to return slightly forward after each notch that it was advanced. This was to prevent the engineer from advancing the throttle too fast (thereby causing vast amounts of wheel slip). They also had a ‘transition’ lever. When C&NW created the “CrandalCab” units, they rebuilt the control stand and put in a regular EMD throttle (without the DB function or the transition lever).
As a further aside note, the early C&NW commuter cab-cars had an old-style EMD throttle assembly which included the ‘transition’ lever, in addition to the throttle and reverser.
The GE’s with 16 had what were know as “half notches”. They’d get you engine speed without the load - an electrical trick designed to help the engr. manage turbo lag, if he cared to. Same basic set of 8 engines speeds.
The Baldwins with 22 had pneumatically controlled governors - heaven help them!
Question: Are other countrys using the 8 position throttles as well? This would include both exports from the US and foreign produced locos. Then we could go into EMUs (domestic and foreign) and other rolling stock. L&N historical society had an article about how the 27 point connector was set up including the 8 throttle positions.
I don’t think that the Budd RDC’s come into this discussion, since they are not diesel-electric, but have a mechanical linkage to the drive wheels. I know that they can be mu’ed with other RDC’s, but I think it would be difficult to run one with a diesel-electric. I have ridden them in both single car and two car operation on the B&O (Washington-Baltimore) and VIA (Vacouver Island).
Try a Google search for “locomotive” & “throttle” & “notches” - as separate words - and see what you come up with. I did one yesterday for that combination, plus “Fairbanks-Morse” as a phrase, and quickly found a detailed explanantion - about 3 - 4 printed pages equivalent, incl. about a half-dozen photos and diagrams (and way over my head, at least for the time I had available to peruse it) - of the Westinghouse throttles as used in Baldwin’s and B-L-H’s several post-war diesel electric systems on a page titled “Baldwin / Baldwin-Lima-Hamilton Control Stands” at :
After reading all the replies it looks to me like is was an ingenious system that worked in the early days of deisel electric when the technology was new, and the reason we do it today is because “that’s the way we have always done it”.
Continuously variable does not require continuous adjustment or constant hands on. Modern fuel controls are very capable and sophistcated. It would be possible to set a speed and let the fuel control maintain it. Turbine powered aircraft have been doing it for decades.
One thing not mentioned so far was that the EMD engine was very sensitive to torsional vibration (remember that the “blade” rod of the fork and blade pair was only held in place by the positive pressure on the piston).
The eight throttle notches and the associated engine rpm settings were carefully chosen to avoid “nodes” of high torsional vibration in the speed range of the 567 engine (and these were again checked for the 567C and 645E which ran at higher speeds).
This was outlined in Eugene Kettering’s paper to the ASME on the development of the 201 and 567 series engines.
I’m glad you guys posted abotu the 16-notch locos. I thought I remembered something about them. As for cruise control, that’d be awesome. Engineer can take a nap while the train drives itself. Eh, I’d be quite lucky to come upon a train that could someday let them do that. Maybe I’ve been watching Knight Rider too much lately…
Cruise control sounds like a good idea, and it is, in my pickup, especially for long trips. I’m sure it would be very helpful over flat terrain in cases where no notch is really right for maintaining the desired speed.
I suspect that the biggest issue with it on trains would be management of slack action. Having the locomotive(s) maintain a constant speed doesn’t take into account the dynamics involved in the rest of that mile-long train over varying terrain.
Perhaps one of our experienced engineers can speak to the concept.
Sorry, but that is not the way I remember them at all. The way you explain it, it sounds like the rod is only floating around in air. Seems to me that the fork rod held the blade rod in place.
And yes, I am old enough to remember those “half notches” on the Alcos & GE’s
Technology might be able to overcome that once detailed train movement mechanics are programmed in to deal with slack action and other stresses, especially with the ECP trains we’ve been having out here, I’d think that kind of thing could be expanded. What all does ECP offer as benefits anyhow? All I know is it pisses off the crews that have to lug them in and work with them, LOL! It’s been a number of times their train has been getting stuck with their lead unit dying on that thing. Anyhow, could wheel-grip detection be included?
Why have notches, and not a continuous throttle???
Don’t forget that the original “Diesels” were really straight electrics with a gen set added. The electric controled speed by sending the 600V (or more) DC thru a set of resistors. Each notch on the controller sent the voltage thru a different combination of resistors till full voltage was applied for full speed. A lot easier for GE or Westinghouse to supply the same controller to the first Diesels.
The PCC streetcars were designed with an almost infinate controller, but by then convention was settling on the diesels, and backwards compatibility was needed.
That would be a conductor’s dream come true! Imagine, not having to go outside on a freezing night in a snowstorm to switch cars! Assuming the switches can be thrown automagically by then, too…I don’t think railroads would have any shortage of employees then!
I remember from a past issue of TRAINS that the main reason for eight notches is that is all the electronic capacity that was available in the early years of diesel locomotive development. The Technology is now available to have unlimited number of notches, like a car, but since eight still work fine, the change was never made.