Eastern Railroad Discussion > New four axle locomotives ????

It seems that the 2 major builders of todays modern locomotives have all but forgotton about the four axle versions. The last new four axles [B40-8s & GP60s] built in the late 80s wont be around forever. So, I was wondering if anyone has a good reason why new four axle locomotives arent being planned. I wonder what a GP70ACE would look like?

I think it had to do with weight distribution, but recent factors have since added to the reasons.

- First, modern prime movers, cabs and high-capacity fuel tanks combine to make a locomotive too heavy for four axles.
- Second, radial trucks reduce rail wear produced by six-axle engines, removing one advantage that four-axle designs had.
- Third, the characteristics of AC traction motors produce six-axle power that can start a heavier train *and* roll it over the road as fast as four-axle power could manage.
- Last but not least, I don't think the larger radiator area neccessary to meet new emissions standards cwould easily be fitted in the shorter carbody of a four-axle unit. It's my understanding that this already contributes to the rebuilding of GP40s, 50s and 60s into "GP38s" which don't have to meet the more stringent standards required of engines over 2000 HP, and therefore don't need the larger radiators.

Awaiting the corrections that I know shall come, I remain:
B-Dubya

Don't think any GP60s have been downgraded to GP38-types yet, and they may not be. One big difference is each type listed before is based on the 645 powerplant. The GP60 has a 710, and apparently, there is no blower (at least yet) for the 710 to allow for it to be deturboed and turned into a "GP38."

One other point on the four axles and today's high horsepower environment-- trying to stick 4000 HP to the rails through four axles instead of six is slippery business. Good for high speed intermodal, but that's about it. Doesn't give as much flexibility, though they still use them on just about anything. I was very happy to see NS stick their back where they belong-- on the pigs.

Mike Derrick
http://www.shortlinesusa.com

There are new 4-axle locomotives being built, but not by EMD or GE. They're putting all their resources behind the big-buck 4,000 to 6,000 hp models. Gerry

GPutz Wrote:
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> There are new 4-axle locomotives being built, but
> not by EMD or GE. They're putting all their
> resources behind the big-buck 4,000 to 6,000 hp
> models. Gerry



Who are "THEY"...we need to know...!

As I am sure you know, Railpower is building quite a few four axle battery powered engines. So far, they are only good for switching, but a road switcher is in the works.

fmw Wrote:
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> As I am sure you know, Railpower is building quite
> a few four axle battery powered engines. So far,
> they are only good for switching, but a road
> switcher is in the works.


They're actually powered by a 290 HP Cat Diesel. When the operation doesn't need 290 HP, the extra goes into the batteries. When more than 290 HP is needed, the batteries make up the difference. When the batteries are fully charged, the engine shuts down.

Not so regarding the Green Goat hybrid and the Cat genset. The diesel genset only charges the batteries, it doesn't provide any power directly to the traction motors.

The previous message said it all regarding the lack of new high-HP 4-motor road locomotives:

1) A 4-axle/4-motor unit is simply uneconomical and undesireable compared to 4300-4400 HP AC or DC road units, because ...

2) You can't carry enough fuel (without exceeding weight limits on 4-axles) to compete with a 5000 gallon fuel tank under a 6-motor unit with the same engine.

3) Most of today's trains are significantly heavier than previous trains. Stack trains typically run up to 8,000 or more tons, compared to 4,000 ton TOFC trains of the 1980s. Coal ... in the west at least, up to 150 cars, and the cars are increasingly becoming all 286,000 pound cars instead of the 263,000 pound car which was maximum in the 1980s. Heavier trains drive more horsepower and more tractive effort.

4) The only equivalence for a 4-motor AC unit (putting out about 90,000 pounds of tractive effort) would be a 6-motor SD40-2 (putting out about 80,000 pounds of tractive effort). But, given the current glut of SD40-2s on the market, no one will pay new-locomotive prices to get a 4-motor AC match for a good used SD40-2.

5) Last, GE and EMD are out to maximum production, factory efficiencies and to make money if possible, and that's why they're increasingly moving toward "standardized" 6-motor AC and DC units. I think you can expect to see fewer and fewer distinguishing "doodads" between the various railroads, with the exception of specialized "have to have's" like cab signals.

Think about all those GP60s and B40-8s still running ... on wayfreights, rock trains, locals and in some cases as switchers. The real reason they're still out running (in the "wrong" applications) is the high residual value on their leases. There's little option except to use them (for what they were never intended) and probably pass them off to the lease market when their leases expire. It really makes no sense (and costs a heap of fuel dollars) to use a 3800HP GP60 as a yard switcher when a 2000HP GP38-2 is adequate, unless you don't have the GP38-2s. And, EMD turbo engines generally don;t last in low-demand switching type work because the turbocharger ends up running directly off the engine gear train through the overrunning clutch (which disengages at around throttle notch 6-7) and you end up with a failed clutch and a smoking locomotive.

Railpower is now building 1900 HP 4-motor switchers for the UP using 3 Deutz 667HP diesel gensets, and National Railway's version is 2100HP using 3 Cummins 700HP gensets. You can't get more than 3 gensets on a 4-axle underframe. You could probably squeeze 4 gensets on an SD50 or SD60 underframe to produce a 2800HP 6-motor genset unit.

NS 215 left Macon this past Sunday afternoon with two GP-60s and a D8-32B. Last week saw another intermodal coming into Macon with GP-50s in the lead followed by a 4-axle GE.

DocJohn
Macon

I have actually seen the higher HP four axles come in quite handy on certain types of yard jobs and heavy transfer assignments. Although they can be slippery, when you are overloaded, you can use every ounce of HP you can get to make it over the next hump.

greendot Wrote:
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> Not so regarding the Green Goat hybrid and the Cat
> genset. The diesel genset only charges the
> batteries, it doesn't provide any power directly
> to the traction motors.

I do believe you're right. Thanks for setting the record straight.

ddkid Wrote:
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> They're actually powered by a 290 HP Cat Diesel.
> When the operation doesn't need 290 HP, the extra
> goes into the batteries. When more than 290 HP is
> needed, the batteries make up the difference.
> When the batteries are fully charged, the engine
> shuts down.

And when the batteries run out of poop, the locomotive falls flat on its face, hence the progressive uprating of the power on the diesel.

ddkid Wrote:
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>
> Not sure where those engines might have come from,
> as EMD has never built a blower 710.

Show me definative proof they didn't...

I don't believe that a 4-axle unit can weigh more than 286,000 pounds; there is no point in building massive horsepower 4-axle units as the horsepower would be of no use since they lack the tractive effort to use it due to the lack of adhesion.

Robbman Wrote:
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> ddkid Wrote:
> --------------------------------------------------
> -----
> >
> > Not sure where those engines might have come
> from,
> > as EMD has never built a blower 710.
>
> Show me definative proof they didn't...

Aside from the impossibility of proving a negative, you'll have to believe me on this. I have close contacts in the Engine Design Group of EMD Engineering, and they say that not only did they not build a blower 710, they never even seriously considered it.

Now, it is possible to prove a positive. Engine model, engine serial number, pictures . . . I'm waiting.

highball Wrote:
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> ddkid Wrote:
> --------------------------------------------------
> -----
>
> > They're actually powered by a 290 HP Cat Diesel.
>
> > When the operation doesn't need 290 HP, the
> extra
> > goes into the batteries. When more than 290 HP
> is
> > needed, the batteries make up the difference.
> > When the batteries are fully charged, the
> engine
> > shuts down.
>
> And when the batteries run out of poop, the
> locomotive falls flat on its face, hence the
> progressive uprating of the power on the diesel.


Yes, it was 90, then it was 130, now it's 290 HP. At this rate, in a couple of years it'll be a 1500 HP EMD.

ddkid Wrote:
-------------------------------------------------------
> greendot Wrote:
> --------------------------------------------------
> -----
> > Not so regarding the Green Goat hybrid and the
> Cat
> > genset. The diesel genset only charges the
> > batteries, it doesn't provide any power
> directly
> > to the traction motors.
>
> I do believe you're right. Thanks for setting the
> record straight.

I certainly don't know, but the design I saw on the Road Switcher definintely had a pretty big arrow going straight from the genset(s) to the control set.

Why no newer HP 4 axles? Easy, plenty of 4 axles around that are not going anywhere. Its been said its easier to buy/lease a SD40-x than to get a 4 motor unit. I saw somewhere that its like 2 or 3 sd's to 1 GP.