• Alco vs. GE Wheel Slip Control

  • Discussion of products from the American Locomotive Company. A web site with current Alco 251 information can be found here: Fairbanks-Morse/Alco 251.
Discussion of products from the American Locomotive Company. A web site with current Alco 251 information can be found here: Fairbanks-Morse/Alco 251.

Moderator: Alcoman

  by Engineer Spike
i was looking at an issue of Diesel Era Magazine. It was the issue about the C430. Part of the article spoke of the New York Central's comparison test of the GP40, U30B, and C430. With Alco using GE electrical gear, was the wheel slip system the same? I can imagine that GE would want to keep this proprietary. Did Alco have the ability to design their own, or was it a GE design?

One would think that if the electrical system was the same, the hi adhesion trucks might be the main difference.
  by Allen Hazen
If you go to Will and David Davis's site, "Railroad Locomotives,"
http://railroadlocomotives.blogspot.ca" onclick="window.open(this.href);return false;
and go through their archive (I think this item would be fairly early in 2010), you'll find a history of the wheelslip control systems GE used on their locomotives from the U25 through the end of the U series: many, many changes and refinements.

My impression from reading the "Diesel Era" article you refer to(*) is that, even if the main electrical components of an Alco locomotive were from GE, the way they were put together was Alco, and there would be some Alco-added "peripherals." (Note that some wheelslip systems had pneumatic as well as electrical components.) And so that the Alco wheelslip control system on the C430 was probably not identical to that used on contemporary GE units. (I also recall thinking that, even after Alco fine-tuned their system after the first tests, it didn't seem much better than the GE system on the U30B... and that the enemy's GP40 was, if anything, the best of the three: did EMD have IDAC at that time?)

(*) Article by Steve Macmillan. Largely incorporated in the "Alco Century Series: four-axle models" book published by the publisher of "Diesel Era."
  by Allen Hazen
As I recall it, the article says that Alco fine-tuned the wheel-slip control on the C430 between the New York Central's first and second adhesion tests. This suggests resetting things, and is consistent with the equipment being re-set being either GE's stuff or a proprietary Alco design.

One possible hint. The GE system at the time made use of individual axle alternators to monitor wheel rpm: each axle had, on the left side of the locomotive, a box on the wheel hub connected by electrical cable to the carbody. Early photos of the New York Central's C430 show the same arrangement of wheel-hub alternators and electrical leads. Suggesting that, whatever the C430 had, it at least resembled the GE system in monitoring single-axle speeds by means of axle alternators.

So maybe GE was willing to sell its long-time customer Alco the equipment, but each builder's engineers separately figured out how to use it, what settings to use... ????

I think this is an interesting question: I hope someone who actually knows something weighs in!
  by Bright Star
U30B and C-430 both had ALDAC (adhesion loss detection and control) wheelslip control-based upon measurement of axle speed via axle mounted AC generators.
One would need to examine the schematics of the locos in question in order to verify differences in equipment, if any.

In contrast, the C-425 used an ECP (FL-148) and an Excitation Panel (FL-50 ?) that were not used on U25B. U25 had 'three field control' (open loop)a la contemporary EMD practice.

There was a control systems group at GE assigned to control equipment design for Alco production.

The SSBV, as used was GE, was used to touch up wheel treads in the case of minor wheel slips. Not standard equipment on Alco.

  by Allen Hazen
Why I love Railroad.net: I ask for someone who knows something to write in, and they do!
Thanks for that information, Brightstar!

So what the Alco engineers did to prepare the C430 for the New York Central's comparative test was to adjust the settings on the GE equipment. (As I recall the outcome, of the three 3000 hp 4-axle models tested, the U30B hauled the greatest tonnage up the hill, but very slowly.)
  by MEC407
Allen Hazen wrote:...the U30B hauled the greatest tonnage up the hill...
You always know how to make me smile. :-D
  by Typewriters
The magazine article, which I recall myself, was interesting, but left some important things unanswered. For example, we don't know for certain whether either the U30B or the C-430 in the test were fitted with Automatic Power Matching. That would make a large difference in the locomotive's performance in the lower speed range, say below 20 MPH. We also don't know for sure whether or not the U30B was equipped with the slip-suppression brake (SSBV) or the All-Electric Wheelslip control. By the time the U30 entered production, the slip brake was the optional equipment and all-electric was the standard.

While it may not be relevant, I can tell you that the NYC U25B units had both Automatic Power Matching, and the SSBV. I can also tell you that the P&LE U28B units had the SSBV, but I can neither confirm nor deny Automatic Power Matching (having only an air piping diagram for these units to confirm presence of the SSBV equipment, but lacking anything definitive electrically to determine power matching.)

The article Allen mentioned that covers wheel slip control on domestic GE U-series locomotives, from the U25 through the U36 is here:

http://railroadlocomotives.blogspot.com ... 5-u36.html" onclick="window.open(this.href);return false;

Readers may wish to note that this article also covers the two styles of Automatic Power Matching employed on the U-series locomotives through the U36, in addition to the developments in wheel slip detection and correction.

-Will Davis
  by Allen Hazen
Relevant points from the article:
---The tests were run at Big Moose, NY, on the New York Central's Adirondack Division: location chosen because the grade was a good simulation of the ruling grade on the Boston and Albany. (Actual grade not mentioned.)
---First test, 9 August 1967. Involved (EMD GP40) 3055, (GE U30B) 2845, and (Alco C430) 430-3. At this time the C430 was about six months old: it was one of the first units built with Alco's "Hi-Ad" truck, the earlier C430 (built for the Reading) having had conventional trucks. (The U30B was even newer: New York Central's second lot of U30B, units 2840-2857, were built in July-September of 1967.) Water leaked into the forward sandbox of the U30B,so usable results were obtained only from the other units.
---(I think this is from a report on the first test): "It is felt that the average speed of the 3055 was higher than that of the 430-3 account the ability of the 3055 to maintain higher average traction motor current because of better wheel slip control" and "No improvement in adhesion which could be credited to the high-adhesion designed truck on Unit 430-3 was noted." (Quoted from NYC test report.)
---McMillan goes on:"In fact, observers on the ground commented that this truck appeared to be quite unstable and 'jumpy' when wheel slip did occur."

---Alco was obviously disappointed. "As a result, Alco made design modifications to the wheel-slip detection and correction system on unit 430-3. After testing at the Alco plant, the builder requested that NYC re-test the unit."
---Further tests were run (using both 430-3 and 430-1) on 28-29 September, 1967, and of the units from the three builders on 8-10 November.
---Best tonnage performances, all on wet rail, and the average speed of the hauls were
------GP40: 1,568 tons at 12.32 mph
------U30B: 1,801 tons at 10.6 mph
------C430: 1,740 tons at 16.25 mph
(Comment: the low speed of the GE unit struck me. Perhaps it was due to automatic power reduction at low speeds if, as Typewriters speculates, the GE unit had Automatic Power Matching.)

Interestingly, New York Central had already, in July 1967, ordered the ten C430 it purchased BEFORE the first test.

(Stephen McMillan's article was in "Diesel Era," vol. 15, no. 5. Rather than look for my copy, I am working from the bit "excerpted" from the article on p. 133 of the book "Alco's Century Series: Volume 1 - Four-axle Models," Withers Publishing, 2003.)