Throttles in 539-powered diesels

I have been looking at the operating manual for the S1, S2, & RS1. It's not clear from the way it's written whether or not the throttle has the usual eight notches, or is infinitely variable, or has some other arrangement of power settings. Does anyone know? In particular, how was it set up on B&O S2s and 4s?

If a 539 is equipped with M.U., it will have an eight-notch throttle. This allows the throttle setting to be passed through the jumper wires to the trailing units. Non-M.U. units have the continuously variable throttle.

JR

That's what I needed to know. Thank you.

I'm guessing that the operator's manual you have been looking at is Alco TP 107A, the operating manual for S1,S2 and RS-1, available on line at George Elwood's marvellous "Fallen Flags" rail image site, at
https://rr-fallenflags.org/manual/s1-gen.html ?
(Also available at at least one other internet site, by the Fallen Flags version is better formatted, and makes figuring out page numbers a bit easier.)
The early sections of this manual don't give details about the throttle, but later (about page 36 or 37), under the general heading of operation of multiple units, the third paragraph of the section "Single Unit Operation" mentions the eight notch throttle.
I think the final control of the engine was by a Woodward governor, which ***I THINK*** (somebody please correct me if I'm wrong) is designed to give a finite number of throttle settings: eight in usual American practice. My ***GUESS*** is that this was Alice's standard offering: whether they built some S1/S2/RS-1 with different controls as customer options, I don't know.

(TP 107A is in the "Fallen Flags" section devoted to manuals. One manual elsewhere on the site -- under "diesel locomotives" in the Pennsylvania Railroad section of "Fallen Flags" -- is a manual the PRR prepared for its enginemen early in the dieselization process giving instructions for Alco, Baldwin, EMD, and F-M locomotives in one book. Doesn't help with the current question, because it only covers 6,000 horsepower, multiple unit, freight and passenger types, not switchers. But interesting.)

I'm guessing that the operator's manual you have been looking at is Alco TP 107A, the operating manual for S1,S2 and RS-1, available on line at George Elwood's marvellous "Fallen Flags" rail image site, at
https://rr-fallenflags.org/manual/s1-gen.html ?
(Also available at at least one other internet site, by the Fallen Flags version is better formatted, and makes figuring out page numbers a bit easier.)
The early sections of this manual don't give details about the throttle, but later (about page 36 or 37), under the general heading of operation of multiple units, the third paragraph of the section "Single Unit Operation" mentions the eight notch throttle.
I think the final control of the engine was by a Woodward governor, which ***I THINK*** (somebody please correct me if I'm wrong) is designed to give a finite number of throttle settings: eight in usual American practice. My ***GUESS*** is that this was Alice's standard offering: whether they built some S1/S2/RS-1 with different controls as customer options, I don't know.

(TP 107A is in the "Fallen Flags" section devoted to manuals. One manual elsewhere on the site -- under "diesel locomotives" in the Pennsylvania Railroad section of "Fallen Flags" -- is a manual the PRR prepared for its enginemen early in the dieselization process giving instructions for Alco, Baldwin, EMD, and F-M locomotives in one book. Doesn't help with the current question, because it only covers 6,000 horsepower, multiple unit, freight and passenger types, not switchers. But interesting.)

Re:

“I think the final control of the engine was by a Woodward governor, which ***I THINK*** (somebody please correct me if I'm wrong) is designed to give a finite number of throttle settings: eight in usual American practice.”


The answer there is “it depends….”

The Woodward New SI and PG governors fitted with integral electro-hydraulic speed control had a finite number of engine speeds, 15 maximum. This was achieved using four speed control solenoids, A, B, C and D, of which the D solenoid also doubled as the shutdown solenoid (on an energize to shutdown basis). This mechanism introduced the well-known triangular plate mechanism upon which the A, B and C solenoids acted. It was introduced with the New SI model circa 1945, and carried over to the PG in the late 1940s. It was covered by US patent 2496284 of

I am aware of the following speed pattern implementations using it, but there are no doubt others:

8 speeds, equally spaced, using all four solenoids, according to the pre-1945 established American pattern, later becoming the AAR pattern, hitherto executed with four-solenoid external electro-pneumatic devices.

8 speeds, equally spaced, using all four solenoids, according to a slightly different pattern used by Lima-Hamilton.

8 speeds, equally spaced, using just the A, B and C solenoids, D for shutdown only.

9 speeds, equally spaced, using all four solenoids, being the AAR pattern with the addition of low idle.

6 speeds, equally spaced, using just the A, B and C solenoids, D for shutdown only.

10 speeds, unequally spaced, using all four solenoids.

14 speeds, equally spaced using all four solenoids.

15 speeds, using all four solenoids plus the overriding solenoid repurposed for speed control, in the Alco DH-643.

The New SI and PG were also available with integral pneumatic-hydraulic speed control. This provided continuously variable speed control, usually directly proportional to control air pressure, between defined limits, the air pressure range being adjusted according to locomotive builder requirements. Solenoid shutdown could be either energize to run (e.g. Alco) or energize to shut down (e.g. EMD). A variation on the control pattern, used by English Electric (EE) and perhaps others, was a divided regime with the first increment of air pressure (30% in the EE case) increasing engine load at minimum speed, and the second increment increasing both engine speed and load.

Where external speed control was used with Woodward governors, then the speed control unit determined the number of settings available. EMD had an external four-solenoid speed control unit that also did shutdown, the governor being fitted with rod shutdown (speed control rod moving in the reverse direction). I have never found a diagram showing the internal works of that unit, though. GE had its own four-solenoid mechanism, the 17MK3, which did the same job. There was also a version of this with just three active solenoids (the fourth omitted and its air cylinder unused) that provided speed control on the MU-fitted Alco 539-engined models, which had a three-solenoid, eight-speed throttle sequence. Here, the three solenoids were labelled T1, T2 and T3 rather than A, B and C. On these, the governors had solenoid shutdown of the energize-to-run type. The non-MU models had direct mechanical control from the throttle handle to the governor. Another variation of the GE 17MK3 unit used all four solenoids to provide seven-speed control on MU-fitted domestic GE 70-ton models. Here the solenoids were labelled T1, T2, T3 and T4. These had Woodward UG8 governors with solenoid shutdown, energize-to-run. (Some export versions of the 70-tonner had seven notch pneumatic control, though.)

Re the locomotives at interest, Alco manual TP-700 might contain the pertinent information on throttle control. It can be found at:

https://www.morscher.com/rr/manuals/Loc ... anuals.htm


Cheers,

Thank you, Pneudyne, for the clarification!
(Also for the link to the Morscher site's collection of manuals: a very useful complement to the collection at "Fallen Flags," including a number of manuals that "FF" doesn't have.)

The manual I have is TP-600, dated 8-51. The section on multiple unit operation starts on page 56, and mentions the existence of throttle notches kind of in passing on page 58.

"

Alco manual TP-700 does appear to have somewhat more detail on the matter.

The Woodward SI governor is dealt with on pages 101 to 122, with the PG on pages 123 to 129. Engine speed setting, with a picture of the mechanical linkage, is on pages 130 to 132.

But the MU throttle operator assembly does not appear until page 1901, with no mention as to how it relates to the governor:



It may be compared with the version used on the GE 70-Ton model, in which all four air cylinders were active:






Cheers,

Somewhat puzzling is the implied question as to why Alco-GE introduced a different eight-notch multiple unit control protocol for the locomotives at interest, when what was (or perhaps what later became) the industry standard protocol already in place.

Absent a commentary from Alco-GE as to why this was done, one is left to construct a (perhaps) plausible rationale, following.

The RME 1940 October article on the Alco 660 and 1000 hp switchers made no mention of a multiple unit control option. A reasonable inference is that it was not offered at the time.

The 1000 hp road switcher was described in RME 1942 February. In particular it was said: “While the basic design of this type of locomotive is essentially the same as the yard switching locomotives which this builder has been delivering for some time, this new type has high-speed trucks; a short additional hood to accommodate the heating boiler; multiple unit control and a higher gear ratio”. This suggests that the MU option was introduced with the RS-1.

For the yard switcher, Alco-GE chose mechanical throttle operation but with electric (solenoid) shutdown of the energize-to-run type. Perhaps it had an aversion to mechanical shutdown (e.g. as used by EMD), or perhaps electric shutdown made it more convenient to effect shutdown from more than one location on the locomotive.

The road switcher without the MU facility followed the yard switcher pattern in respect of throttle control and engine shutdown. Evidently Alco-GE wanted to retain the same (Woodward SI) governor, including solenoid shutdown, for the MU option, and that was most easily done by using a suitable eight-position electropneumatic speed control. This outruled the “standard” eight-notch system, which required a governor with rod shutdown, and a nine-position governor operator where the first position effectively provided an energize-to-stop facility.

Accordingly, the GE 17MK3 four-solenoid, nine-position electropneumatic governor operator was modified to delete the fourth solenoid and to provide eight positions from the remaining three. Alco-GE used a normal three-wire binary code for its control. The standard system had a four-wire modified binary code. This could be attributed to a desire to introduce some elements of the Gray code (one change at a time), but it might also have been to ensure that the fourth (D) solenoid and particularly its air-cylinder did get some regular “exercise” in normal operation by being used in for notches 5 and 6. Perhaps this made it less likely to stick and so fail to function when engine shutdown was required.

Evidently Alco-GE did not envisage that mixed MU operation of the RS-1 with road locomotives would be required. In 1941 MU mixing-and-matching of different makes and models of road locomotives was probably uncommon; mixing road locomotives and road-switchers would have been even more of a stretch.


Cheers,