Informations about GP35, GP7/9 an SD70

Hello,

I hope a have chosen the right forum. First I want to visualize me. My Name is Andrew (Andreas), I'm 18 years old and come from Germany. I hope you understand my English, I haven't wrote much English since my school-time. I'm very interested in model-railroads an collecting Z-Scale models.

Since a few of month, here in Germany one of my friends releases a new free online-magazin. It calls TRAININI (www.trainini.de). I want to help him to get noted for his magazin, and want to write some articles for this magazin.

Because Micro-Trains has built an EMD GP35 in Z-Scale last year I want to write an article about this machine. But I haven't found much information in the internet by google. There are so much commercial founds, and so less private sites.

Now I ask you to help me. I need some important information about this locomotive, as

How many built? When built? For what services built? Which phases built, and where are the differences between? For what companies built? And much more.

Also I need pictures of the loco that I can use in the magazin. And it would be good if someone can mail me a short text about EMD.

Can someone please tell me URLs where I can find these information? Or can you send me some texts by e-mail? ([email protected])

And finally I need the same information for the GP7/9 and the SD70. These engines will be released this year as models.

I know that are very much questions I ask, but please help me.

Thanks for reading, an I hope you have understand all I wrote.

Regards

Andrew (Andreas)

Guten Tag Herr Andreas,

First off; your written English is a lot better than some I have seen here. You obviously took the time and effort to be concise, and intelligible. Congratulations.

GP-35: Data from Jerry Pinkepank's "Second Diesel Spotter's Guide". I believe the book is still available.

2500 Horsepower from 16 cylinders using a 567D3A diesel engine.

Period Produced; 10/63 to 1/66

Total number produced; USA -- 1250
Canada --26
Mexico -- 57

Hope that helps out. Regards

Wie Gehts Herr Andreas,

The GP-7 and GP-9 are somewhat more complex since they came in A and B units. I'll give you the data on the A units, should you need the data on the B units let me know. The Reference is the same as the GP-35.

GP-7: 1500 hp from 16 cylinders using a 567B Diesel Engine
Produced from 10/49 to 5/ 54

Total Production; USA -- 2610; Canada -- 112; Mexico -- 2


GP-9: 1750 hp from 16 cylinders using a 567C Diesel Engine
Produced from 1/54 to 12/59 (In Canada to 8/63)

Total Production: USA -- 3436; Canada -- 646; Mexico -- 10

Good Luck

By the way, All engines you cite are made by ElectroMotive Division of General Motors (EMD)

Hi,

Had to do some hunting for the SD-70, but here it is. Also an EMD engine.

SD-70, SD-70M and SD-70MAC

4000 hp from 16 cylinders from a 710G Diesel Engine.

All have AC traction motors. All are still in production.

Reference: "The Contemporary Diesel Spotter's Guide", Louis A. Marre

Hope all of this solves your problems.

Greetings Andrew, you can find a roster of GP35s by owner with phase information here: http://users.inna.net/~jaydeet/rosters.htm

EMD Serial Number information is here: http://community-2.webtv.net/ajkristopans/ Andre Kristopans has an excellent page with the EMC/EMD serial numbers recorded mostly by date and by locomotive type.

You can find a lot of basic EMD locomotive information here: http://en.wikipedia.org/wiki/General_Mo ... e_Division

Drop me a line as I have photos that you could use.

Hello,

first thanks for the information. I will explore the thre pages this week. But what I haven't found after a first look are the answers for the following questions:

- For whitch kind of Trains was the locomotive developed for?
- Who wanted the development of this type?
- Has it really mostly been pulling this trains?
- Where does this loco mostly run, or is it in the whole USA (+Canada)?
- How many of the built locomotive are still running on rails?

- What technical criterias has the locomotive, like brakes, engine, cooler...?

First only for the GP-35. This is the first article I'm going to write.

And now I have an general question for testing locomotives in USA. Pennsy wrote that the GP-35 has 2500hp. How and where did they detect it? Right after the engine? Or what performance the locomotive has on the rails? (I hope you understand what I mean)

Ok, I think when I got the answers of this questions, I can write my first article.

Many thanks.

Regards
Andrew

pennsy wrote:Hi,

Had to do some hunting for the SD-70, but here it is. Also an EMD engine.

SD-70, SD-70M and SD-70MAC

4000 hp from 16 cylinders from a 710G Diesel Engine.

All have AC traction motors. All are still in production.

Reference: "The Contemporary Diesel Spotter's Guide", Louis A. Marre

Hope all of this solves your problems.

I don't think they're all AC. According to standard EMD practice, the variations are:
SD-70: Standard cab, DC traction
SD-70M: Wide cab, DC traction
SD-70MAC: Wide cab, AC traction

Andreas wrote:Hello,

first thanks for the information. I will explore the thre pages this week. But what I haven't found after a first look are the answers for the following questions:

- For whitch kind of Trains was the locomotive developed for?
- Who wanted the development of this type?
- Has it really mostly been pulling this trains?
- Where does this loco mostly run, or is it in the whole USA (+Canada)?
- How many of the built locomotive are still running on rails?

- What technical criterias has the locomotive, like brakes, engine, cooler...?

First only for the GP-35. This is the first article I'm going to write.

And now I have an general question for testing locomotives in USA. Pennsy wrote that the GP-35 has 2500hp. How and where did they detect it? Right after the engine? Or what performance the locomotive has on the rails? (I hope you understand what I mean)

Ok, I think when I got the answers of this questions, I can write my first article.

Many thanks.

Regards
Andrew

Andrew,

To answer just a few questions, all three of these models (grouping the pretty much similiar GP7s and GP9s) together, all were designed for freight service, and that's what they largely saw. EMD did design in provisions for steam generators for passenger service (for heating the coaches) in the GP7/9, and there were many (but still a minority of the total built) that came set up for passenger service. Several northeastern railroads found the road-switchers like the GP's and Alco's RS-3's ideal for commuter service, since they didn't need to be turned at the end of runs.

If you do some more in depth research into the GP7/9, you'll find a very fascinating history. EMD was the last diesel builder at the time to add the road-switcher configuration to its catalog. While the cab unit (EMD F-units, Alco FA's, etc.) were envisioned as the original freight diesel, railroads quickely learned that a unit that could easily be used for road service or switching is much more useful. Given the diesel's mechanical flexibility, there wasn't the need to design limitations such as cab unit carbodies into them. Alco and Baldwin started road-switcher design early, but EMD resisted until the GP7 was introduced in 1949. Its design was often said to be "ugly enough that railroads would want to relegate it to the last backwoods branchline where steam still hung on," or something to that effect.

Needless to say, EMD went on to far outsell Alco or Baldwin despite their late entrance to the road-switcher market. Today, many GP7s and 9s survive on shortlines and regionals, and even a few rebuilt ones on some major railroads.

The I don't think that there were ever any GP35s set up for passenger service. By the 1960s, most North American roads weren't looking to buy any more passenger motive power. I'm sure that there are some instances of GP35s being used on passenger trains, but they would need to be MUed with other units that are equipped for passenger service, as I don't recall ever reading about GP35s equipped to provide steam or head-end (HEP) or hotel power.

The SD70 series also was designed solely for freight service. The one exception is the Alaska Railroad's SD70MAC, which were designed to allow use of an AC traction power converter to supply either traction power or HEP, for use on ARR's passenger trains. ARR's units are intended for both passenger and freight service. To my knowledge, they are the only ones with this feature (can't imagine any of the other SD70 customers needing this feature).

Some info on the ARR units from Siemens, which supplies the AC electrical equipment to EMD:

http://references.transportation.siemen ... div=6&l=en

Hope this helps.

Hi All,

Interesting information, even though some of it is conflicting.

GP stands for General Purpose. That explains why these engines were used in such widespread applications.

SD stands for Severe Duty. These have C-C (Co-Co) trucks, with all axles powered. This was designed to be the freight work horse, or used for Severe Duty.

And, you are a fountain of questions. More power to you.

Anyone care to go into Turbocharging ? EMD shied away from that addition for quite some time, until Union Pacific turbocharged a GP-9 successfully, giving it 2000 hp. They showed EMD how to do it.

pennsy wrote:Hi All,

Interesting information, even though some of it is conflicting.

GP stands for General Purpose. That explains why these engines were used in such widespread applications.

SD stands for Severe Duty. These have C-C (Co-Co) trucks, with all axles powered. This was designed to be the freight work horse, or used for Severe Duty.

And, you are a fountain of questions. More power to you.

Anyone care to go into Turbocharging ? EMD shied away from that addition for quite some time, until Union Pacific turbocharged a GP-9 successfully, giving it 2000 hp. They showed EMD how to do it.

SD: Severe Duty, or Special Duty? Not that there's much difference, just curious.

jg greenwood wrote:

pennsy wrote:Hi All,

Interesting information, even though some of it is conflicting.

GP stands for General Purpose. That explains why these engines were used in such widespread applications.

SD stands for Severe Duty. These have C-C (Co-Co) trucks, with all axles powered. This was designed to be the freight work horse, or used for Severe Duty.

And, you are a fountain of questions. More power to you.

Anyone care to go into Turbocharging ? EMD shied away from that addition for quite some time, until Union Pacific turbocharged a GP-9 successfully, giving it 2000 hp. They showed EMD how to do it.

SD: Severe Duty, or Special Duty? Not that there's much difference, just curious.

IIRC Special Duty was the original term. Back when they didn't envision things like radial trucks and 4000+ HP prime movers...

Andreas

Here is a link to a web site with manuals for various locomotives.

http://www.rr-fallenflags.org/manual/manual.html

Joe

Interesting thread.

The EMD model prefixes were/are GP for "General Purpose" and SD for "Special Duty." The SD series first appeared in the 1950's as a response to six-axle, six motor units built by Baldwin (first) and then by Fairbanks-Morse and ALCO-GE. They were originally intended for heavy low speed service, including drag service, transfer service and hump service.

As the years went on, the amount of horsepower available from a single diesel engine increased and some roads (and builders) felt that the only way to successfully apply this power was through six driving axles. The F-M Train Master was an early harbinger of this trend, but it really kicked off in the early-mid 1960's with the then-famous but seemingly now-forgotten "six axle debate" largely due to the efforts of the Atlantic Coast Line and ALCO.

The GP-35 was one of those units being built at the time of this changeover on many roads from four-axle to six-axle power, and included a feature called Drag Duty Performance Control (first introduced in the GP-30.) This feature reduced excitation of the main generator at speeds below about 18 MPH so that, by the time about 12 MPH was reached the locomotive was developing 2000 HP for traction. EMD felt that this feature allowed most roads to avoid the expense of six-axle units and would allow these units to operate compatibly with older units which had comparable minimum continuous speeds. For those who felt that the feature was not sufficient, EMD did introduce a six-axle SD-35 which did not have any power reduction features. This should help place the two types in better context with each other.

The HP rating of these units is horsepower delivered to the generator. It is not diesel engine brake horsepower, since auxiliary load is accounted for, except the air compressor (which cycles) -- and it also is not output from the generator.

As to "who wanted development of the type," the GP-35 was simply a logical step in the progression of units from EMD and was the replacement for the GP-30 in the catalog. It was the first EMD unit to equal the horsepower ratings already being offered by General Electric and by ALCO. It was also the last generation of pure DC units; the D32 main generator was absolutely at its limit producing this power, and the next generation of units introduced both alternator-rectifier transmission and the new 645 engine to go with it. (The new, 1965 GP-38 DID have a D32 generator, which quickly was amended with the option of the AC-DC transmission for those who wanted it at extra cost.)

A good average all-up weight for the GP-35 as purchased by most roads was around 262,000 lbs. At the normal assumed 25% adhesion for starting this yields a starting tractive effort of 65,500 lbs. The continuous rating of the unit was 51,700 lbs. tractive effort at 12 MPH.

This can be compared with the six-axle SD-35 using the same engine and generator, but weighing 389,000 lbs. with a starting tractive effort of 97,250 lbs and a continuous rating of 75,000 lbs at about 9.4 MPH. It is immediately obvious what advantage can be obtained through use of this unit, developing power through six rather than four motors, taking full advantage of the possibility for weight increase obtained through use of six axles.

EMD was often quick to point out that most roads would not obtain much advantage through use of the SD rather than GP models, since above a certain speed the actual pull at the drawbar was roughly the same, but many roads with steep grades felt that using more GP-35 units than SD-35 units was wasteful in terms of number of units needed for tractive effort.

Having said that, although the GP-35 had its share of problems (most notably with a complicated field shunting system designed to protect the generator from overload and flashover) the GP-35 could be found on many important US trunk lines at the head of the fastest, most important freight trains for a number of years. On Conrail, I clearly remember the very fast Flexi-Van piggyback trains being headed with mixtures of the newer GP-40 and GP-40-2 units, but very often with the older GP-35 units still mixed in, during most of the 1970's.

Some comment was offered on turbocharging, which really dates further back to the SD-24 and the GP-20. UP did in fact turbocharge EMD engines before EMD did, but it used a setup not unlike that employed on the Russian-built M62 ("Taigatrommel") type with both Roots blower and turbochargers -- the compressed air from the turbochargers was fed into the Roots blowers, to ensure proper scavenging at all engine speeds and loads. The much more elegant (and practical) solution arrived at by EMD was to include gear drive for the turbine rotor and an overrunning clutch, so that when exhaust boost pressure became high enough that it could take over drive of the rotor and accelerate it above gear train speed, the rotor would out-rotate the clutch element and spin much faster. This was necessary because in two-stroke engines, the intake and exhaust passages are actually in communication with each other through the cylinders during scavenging, and due to the fact that the scavenge time is incredibly short at the speeds the engines were running. (That is an oversimplification that many will catch, but should suffice as a beginning point for our new friends.)

Finally, as with most types, the GP-35 was eventually superseded by newer units with more horsepower (and on many roads with six axles,) and eventually was to be found in all sorts of secondary service, even including yard switching (which I personally observed at the Conrail Rockport Yard in the early 1990's.)

I hope this has answered some of your questions, and I'll certainly check back to see whether it has, and if you have more.

-Will Davis