The EMD GP-9

tyler_phillips · Wed Sep 10, 2008 11:25 am

Why do some EMD GP-9's look different than others? Example, let's use the Adrian & Blissfield Railroad's GP-9's.

- ADBF 1751

http://www.rrpicturearchives.net/showPi ... ?id=890649

This GP-9 has no bump out on the long hood.

- ADBF 1752

http://www.rrpicturearchives.net/showPi ... ?id=757962

This GP-9 has a bump out with vents in it, on the long hood.

- ADBF 1760

http://www.railroadmichigan.com/adbf1760a.jpg

This GP-9 has the bump out, but no vents in it. ADBF has 3 other GP-9's like this one.

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SD80MAC · Unread post by **SD80MAC** » Wed Sep 10, 2008 11:37 am

1751 has no dynamic brakes, 1752 has dynamic brakes, and 1760 had dynamic brakes at one time but it looks like they were removed and the grids were plated over.

Unread post by **AARR** » Wed Sep 10, 2008 12:15 pm

In addition to dynamic brakes there are many other features that can change the appearance. There's several books out there that show the differences between engines.

For example, GP9's were built in four or five different styles that in many ways they look the same but then again different. For example:
Ph 1 - Looks sorta like GP7 with different grills under cab and along hood
Ph 2 - Changed grills on long hood
Ph 3 - Changed side sills
Ph 4 - Changed from 4-24" fans to 2-48"
Ph 5 - Chop nose and rearranged air and fuel tanks
Add to the above some units (usually in passenger service) have air tanks on top of long hood.

If someone has time maybe they can post here pics of some of the differences.

tyler_phillips · Wed Sep 10, 2008 12:59 pm

What exactly are dynamic brakes? And as for 1760, why would they have removed them?

sd70accsxt700 · Wed Sep 10, 2008 1:19 pm

In "Power" mode, the prime mover (ie. Diesel), turns a generator to make electricty, and the electricity goes to the traction motors on the axles and turns them. In dynamic breaking, it is the opposit. The tracton motor armatures are turned in revers, (go backwards in effort), thus creating electricty insted of using it. This retards the axles, the electricty is ran to a resistor grid, (think toaster), and is disapated as heat. What you see is the air intake on the side of the hood, and a fan on the top. The dynamic brake handle, slides, and does not have notches, as per say the throtle does. It still consits of eight "notches" or positions, but all variable.

Its likened to this.

Using the gears in a stick shift, car, to slow you down. Unlike shifting up to gain speed, you shift down to slow the car down.

As far as having them removed they dont need them anymore where they opperate. Dynamic braking is a means of slowing and stopping the train with out the use of air brakes to stop. Depending on the size of the hill, dynamics can control your speed, with out using air also. Or in the olden days strech braking, where you take air and throtle aginst it to keep the slack streached. Dynamic braking uses less fuel then strech breaking. Thus saving money. Most railroads that did not encounter heavy grades, did not order dynamics, ie. NKP, RFP, RI, KCS, ect. Now days all order them with them, as a fuel saving device.

tyler_phillips · Wed Sep 10, 2008 1:24 pm

Oh, I understand. Why would they remove Dynamic Brakes on some locomotives?

sd70accsxt700 · Wed Sep 10, 2008 1:25 pm

Bottem half explains why, sorry I missed the question the first time, and was editing it. Also back then, it cost more money for the option, so those that didnt need it did not order it.

tyler_phillips · Wed Sep 10, 2008 4:35 pm

What are the average "life spans" of locomotives? Like, the "youngest" of the ADBF fleet is 51 years old, with the oldest being 53 years old. How long can these go?

Unread post by **AARR** » Wed Sep 10, 2008 4:57 pm

What are the average "life spans" of locomotives? Like, the "youngest" of the ADBF fleet is 51 years old, with the oldest being 53 years old. How long can these go?

If they're well maintained they can probably go another 10 or so years and then ADBF will have to decide what to do at that point.

tyler_phillips · Wed Sep 10, 2008 6:34 pm

If they're well maintained they can probably go another 10 or so years and then ADBF will have to decide what to do at that point.

What would therre options be? I wonder because they just bought 4 more GP-9's in 2004, using 2 of them and the other two are for sale. I wonder why they would buy 4 more if they were only going to last another 10 or so years.

Would they have to be re-built or sold off and buy newer locomotives?

leo28150 · Unread post by **leo28150** » Wed Sep 10, 2008 8:55 pm

Most likely the lifespan of these engines will depend on the wiring and major components--i.e., main generator-- as these are big money items to replace. These engines are pretty much indestructable, EMD started having 'issues' with them when they started putting turbos on the 567 engine; personally, I love 'em. I had the opportunity to run GP-7s' and -9s' on the IN for 7 years---what they had at the time I was there---and they did a good job. Hook a couple of them up together, have dry rail, add a little sand and you could pull ANYTHING. As for the dynamic brakes, the grids usually were the first to go; hence, if they aren't working, disable them and plate over the openings to help prevent moisture coming into the engine area. On these older units, the dynamics usually cut out around 10-12 mph or were very ineffective at that speed and lower; a 10 mph rr wouldn't get much use out of them to make them cost efficient to maintain.

tyler_phillips · Wed Sep 10, 2008 10:31 pm

That is very interesting, I have heard that the Adrian & Blissfield Railroad take excellent care of their equipment. What was EMD's replacement for the GP-9?

leo28150 · Unread post by **leo28150** » Thu Sep 11, 2008 12:05 am

EMD started the upgrade with GP-18s' and GP-20s'; the 18's were rated at 1800 hp and the 20's were at 2000 hp which they got by using a turbocharger instead of the Roots Blower.

hobojim · Unread post by **hobojim** » Thu Sep 11, 2008 3:40 am

leo28150 wrote:EMD started the upgrade with GP-18s' and GP-20s'; the 18's were rated at 1800 hp and the 20's were at 2000 hp which they got by using a turbocharger instead of the Roots Blower.

I know turbocharging, supercharging etc. What is the difference between turbocharging and a roots blower?
thanx
Jim

leo28150 · Unread post by **leo28150** » Thu Sep 11, 2008 7:47 am

The blower was used to get air into the engine.

tyler_phillips · Thu Sep 11, 2008 1:18 pm

Was the GP-9 designed so that when it is traveling with the long nose forward, it is going "forward"? And short nose forward, it is going in "reverse"?

Unread post by **AARR** » Thu Sep 11, 2008 2:37 pm

Was the GP-9 designed so that when it is traveling with the long nose forward, it is going "forward"? And short nose forward, it is going in "reverse"?

Most were designed for the short end to be the front. Some, like CN, GTW, NYC, operated long end as the front. It's just a matter of switching what side the controls are on.

Unread post by **AARR** » Thu Sep 11, 2008 2:39 pm

Tyler, there are nice, inexpensive books out there with loads of this info. You can look them up online or go to your nearest hobby store. I'm like you...I really like this sort of info, and my small library of locomotive indentification books have been a huge help to me.

Mick · Unread post by **Mick** » Thu Sep 11, 2008 4:30 pm

hobojim wrote:What is the difference between turbocharging and a roots blower?

Jim, "Roots" is a brand name. Their blowers are gear driven from the engine, and provide the pressurized intake air that a two-stroke diesel needs to operate properly. Sometimes this is referred to as "Normal aspiration". A four-stroke diesel utilizes the vacuum of the piston moving down in the cylinder to charge it with air before the compression stroke begins. With a two stroke, air under pressure must enter the cylinder for the brief moment that the piston is near bottom dead center. The air displaces the exhaust out through the exhaust valves, which close with a fresh charge of air for the compression stroke.
A turbocharger (Whether used in a two or four-stroke engine) has an exhaust turbine on one end of a shaft, and a blower wheel on the other end. Engine exhaust forces the shaft to spin by acting against the turbine. The blower wheel on the other end produces the pressure needed to force an adequate volume of air into the air-box (On a two-stroke) or the intake manifold (On a four-stroke). As engine speed increases, air volme increases proportionately. That provides a significant increase in horsepower.

Mick

tyler_phillips · Thu Sep 11, 2008 6:32 pm

Don, I am very new to this web site and "railfanning," so I don't know of any books and a lot of general train information. What are some books that you might recommend? I'm very interested in the EMD models, especially the GP-9. Also interested in the Indiana & Ohio, Adrian & Blissfield, and Norfolk Southern Railroads, just incase you knew of any books that may include those three.

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