A question re: EMD's GP28/SD28 locomotives

[Anonymous]

Here's my question: are the GP28 and SD28 locomotives simply updated versions of the earlier GP18 and SD18 models (newer style carbodies, improved prime movers, electricals, same horsepower), or was there another reason for EMD producing these relatively rare locomotives?

[Anonymous]

Thank you for the answer! [:)] Btw- does IC now CN still have that one operable former C&G SD28, or is it long gone?

[fuzzybroken]

The GP/SD28 models were actually the next progression up from the GP/SD18. The GP/SD18 were the non-turbocharged versions of the GP20 and SD24, while the 28s were the non-turbo versions of the 35 line. So they had the newer carbodies, prime movers, etc., including the new pressurized carbody et al.

Although I am in some principles disagreeing with Mark, he also makes several good points, mostly about the marketing of the 18s vs. the 28s. Turbochargers were a new technology on EMD engines at the time the 18s were introduced, so EMD seems to have given equal footing to the 18s and the GP20/SD24. By the time the 28s and 35s came along, EMD had proven that their turbochargers were worthy equipment (with the oddball GP30s in-between), so there was much greater marketing of the 35s than the 28s.

But the 38 series ended up being much more popular! Which was the next progression from the 28s.

[2c],
-Mark
http://www.geocities.com/fuzzybroken

[Anonymous]

A GP28/SD28 is basically a de-turboed GP35/SD35.

[Allen Jenkins]

Also, don't forget, the research & development of internal power systems, such as the factor of manual transition from series to parallel traction, the competition of ALCo, with the Century, and General Electric U25 series, against then proven technologies. Just the competition for market share sales, gave us the GP30, with just 2250 hp. Whilst EMD worked out the internal bugs on the 35 line, the GM Automotive design guys gave us the gift-wrapper, to a locomotive which has now lasted 40 years, albiet de-turbocharged, auto-transitioned, and da***wo upgraded. So the GP/SD28, was part of this interim scheme of things, a low priced, medium horsepower unit, which used the trade in trucks, engine block, and traction motor cases, if useable, from Funits, and or SD wreaks, trade in's.

[M636C]

Mark,

Did you get up early or not go to bed?

The recent extrapolation of the six axle development so that all road freight locomotives are now six axle confuses the family tree.

In Australia we had light track, so we had six axle F units, most of which were six motor, and reflecting comments in the "SD79" thread, we have six axle 12-710 locomotives in fairly wide use on both narrow and standard gauge. We even have twelve cylinder, AC traction, narrow gauge EMDs in service.

On Wednesday, I was looking at a recently overhauled and repainted cowl unit with a 12-710, Pacific National's DL 46. This is known as an AT46C in the export series. In the US , would this be an F59C or maybe an SD59F?

Peter

[Anonymous]

Maybe I didn't see the lettering right, but what's a GP15?? It's not in my editon of the spotters guide. I saw 2 of them switching auto-racks on the UP at West Chicago not too long ago. No turbos or dynamic brakes, but they do have low hoods and the older style UP yellow paint scheme and lettering. I'm guessing they're modified GP7s???

[M636C]

No, a GP15 is a new unit built as an alternative to a rebuilt GP7 or GP9. It could be regarded as a development of the SW1500, with which it shared the twelve cylinder 645E engine of 1500 HP. The SW1500 could be built with two axle Flexicoil trucks which made it suitable for road use. Later versions were built with "Blomberg" two axle trucks, like GP units, the Mexican SW1504 and the MP15 and MP15AC.

A logical extension of this idea was to build a "proper" roadswitcher, with the 12-645E but with a standard, low nose cab. Initially, these GP15s had DC generators, no central air system and built to a low price. Later units had central air systems, dynamic brakes, and a few units were GP15T with turbocharged eight cylinder engines, which would improve their fuel economy in road service.

Conrail, MoPac and Chessie bought a lot of them.

Peter

[Allen Jenkins]

One for "printable version". ALCo636 is right, the SD79 thread also addresses some of these issues. History in the perspective is in play. I was taught the criteria Mark has given, the perspective of the day. The GP15, for instance. That locomotive was initially offer as a rebuild option, by the builder, using the frames, engine(upgraded to Series 16V645 specs), trucks, and traction motor cases. The result, was the GP15-1. The GP15-1, offered a roadswitcher platform, a standardized cab layout, and the Brotherhood (union), toilet space, in the nose, and also offered a little privacy, or normalcy, which no SW could provide. That's why the GP15-1 has no dynamic braking, as the rebuild units offered no reason to add this brake shoe saving option. Someone, railroad, or builder came up with the enterprising effort, of using this four axle platform, with a turbocharged Series 8V645 engine, rated 1500hp, new traction motors, and AC traction generator of the day, and the GP15T was born, complete with a sleeping cat on the hood. The Chessie System even ran them as mainline power, albiet to offset the stinging cost. At this time the competion had fielded over one hundred U18B, V8 7FDL 1800hp locomotives, for a couple of lines.

[Randy Stahl]

It sure seems that the horsepower race of the early 1960s produced alot of locomotives before they were ready. The worst example I can think of is the SD-24. This locomotive has the appearance of being designed at a bar after hours. Good god..17 steps of transition... All because they couldn't wait for a decent generator. Thank the RR gods for the inspiration for the AR-10.
Randy

[Anonymous]

QUOTE: Originally posted by Allen Jenkins

One for "printable version". ALCo636 is right, the SD79 thread also addresses some of these issues. History in the perspective is in play. I was taught the criteria Mark has given, the perspective of the day. The GP15, for instance. That locomotive was initially offer as a rebuild option, by the builder, using the frames, engine(upgraded to Series 16V645 specs), trucks, and traction motor cases. The result, was the GP15-1. The GP15-1, offered a roadswitcher platform, a standardized cab layout, and the Brotherhood (union), toilet space, in the nose, and also offered a little privacy, or normalcy, which no SW could provide. That's why the GP15-1 has no dynamic braking, as the rebuild units offered no reason to add this brake shoe saving option. Someone, railroad, or builder came up with the enterprising effort, of using this four axle platform, with a turbocharged Series 8V645 engine, rated 1500hp, new traction motors, and AC traction generator of the day, and the GP15T was born, complete with a sleeping cat on the hood. The Chessie System even ran them as mainline power, albiet to offset the stinging cost. At this time the competion had fielded over one hundred U18B, V8 7FDL 1800hp locomotives, for a couple of lines.

Thanks for clearing that up. These two were definately not turbo-charged but the low hood looked like it came out of EMD rather than some home-grown rebuild. They were pulling really hard to get a long string of empty racks up to ~10 mph across the diamonds at West Chicago.

[SSW9389]

I don't think Illinois Central initially used its dozen GP28s on the branchlines. Nor Chihuahua Pacific's 10 GP28s or South Peru Coppers five units. The TexMex and KO&G were short haul operations, as was Mississippi Central. We could go round and round on this, but some railroads did not want turbocharged power. The GP28 was based on the same 567D1 engine as the GP18. The electronics and carbody were updated in the 28 series from the 18s.

I don't consider Reserve Mining's four SD28s as being used on a branchline either. Reserve was a heavy haul iron ore carrier in Minnesota.

See X2200 #36 for data on the Geeps.

[Allen Jenkins]

"And how much it costs." Mark Hemphill. ACJ. Add future.

[tomclark01]

great answer on sd28 - i dispatched for 30 years and never came across one

[samfp1943]

[quote user="tomclark01"]

great answer on sd28 - i dispatched for 30 years and never came across one

[/quote]

Tom Clark01:  CAGY (nee: C&G RR)  Was not far from my Memphis roots.  Had famiy in the area and even hauled a lot of cotton from the Miss Delta.  Here is a pretty good resource for things CAGY.

Linked @ https://www.american-rails.com/cagy.html

Beforee the C&G came into being it was the Southern Rwy and at Morehead, Miss. the Southern (E-W line) crossed the Yazoo Delta RR (N-S line) locally known as the 'Yellow Dog'. It was in honor of that jct @ Morehead, Ms. that Blues songwriter W.C. Handy wrote the ballad " Where the Southern cross The Dog' {aka: " Yellow Dog Blues' .

Here is one linked vid: @ https://www.youtube.com/watch?v=DOzlVXmRURw

[CSSHEGEWISCH]

tomclark01

great answer on sd28 - i dispatched for 30 years and never came across one

 

Not too surprising, only 6 were built for domestic service, 4 on Reserve Mining Co. and 2 on Columbus & Greenville.