Author Topic: New power for Metra, the SD70MACH  (Read 2149 times)

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sd45elect2000

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Re: New power for Metra, the SD70MACH
« Reply #15 on: October 13, 2022, 11:04:32 AM »
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Yeah, but... physics. ~208+ tons for a 70MAC vs. ~114 tons for an F40 is a lot of additional mass to overcome. Firmware can't fix that. Proof will be in the pudding.

The weight is going to be its biggest asset. The F-40 is going to slip. The SD70 can really pour on the torque. Starting tractive effort is close to twice the F-40.

nickelplate759

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Re: New power for Metra, the SD70MACH
« Reply #16 on: October 13, 2022, 11:10:52 AM »
+1
Yeah, but... physics. ~208+ tons for a 70MAC vs. ~114 tons for an F40 is a lot of additional mass to overcome. Firmware can't fix that. Proof will be in the pudding.

As a software engineer by trade, I hate that people often expect software to "fix" hardware design problems.
George
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I'm sorry Dave, I'm afraid I can't do that.

Pizzaparty

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Re: New power for Metra, the SD70MACH
« Reply #17 on: October 13, 2022, 12:38:51 PM »
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Remember that these big engines already pull 70 mph stackers on a regular basis, the weight of a bi level coach car and an intermodal car with two containers is pretty similar (assuming a tare weight of a well car at 55k and two containers at 45-50k each for a total of 150k which is 75 tons) and a coach bi level car cooking in around 65-70 tons.

And the commuter trains seldom sustain max speed in Chicago.

It’s a decent business move for Metra, not the best, but it’ll do with limited budgets

Edit - the bigger problem is who’s gonna make some decals for n scale?
« Last Edit: October 13, 2022, 12:43:34 PM by Pizzaparty »

Philip H

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Re: New power for Metra, the SD70MACH
« Reply #18 on: October 13, 2022, 12:58:50 PM »
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Quote
Edit - the bigger problem is who’s gonna make some decals for n scale?

And will those decals alleviate the need for masking when one paints?  :trollface:
Philip H.
Chief Everything Officer
Baton Rouge Southern RR - Mount Rainier Division.


nickelplate759

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Re: New power for Metra, the SD70MACH
« Reply #19 on: October 13, 2022, 01:31:57 PM »
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And will those decals alleviate the need for masking when one paints?  :trollface:

Fusion Scale Graphics announced decals this week.
https://fsdecals.com/collections/railroad-decals/products/fsg-metx123-160
George
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CBQ Fan

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Re: New power for Metra, the SD70MACH
« Reply #20 on: October 13, 2022, 07:20:15 PM »
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Remember that these big engines already pull 70 mph stackers on a regular basis, the weight of a bi level coach car and an intermodal car with two containers is pretty similar (assuming a tare weight of a well car at 55k and two containers at 45-50k each for a total of 150k which is 75 tons) and a coach bi level car cooking in around 65-70 tons.

And the commuter trains seldom sustain max speed in Chicago.

It’s a decent business move for Metra, not the best, but it’ll do with limited budgets

Edit - the bigger problem is who’s gonna make some decals for n scale?

If they are pulling express trains their top speed has to be near the max in some stretches. Having been on them and standing on the platform when they went by they are hauling.
Brian

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Bulbous

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Re: New power for Metra, the SD70MACH
« Reply #21 on: October 13, 2022, 07:35:08 PM »
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Shouldn't the big question be - Why do you need a ~34 tonne axle load locomotive to haul around passenger cars on a suburban network?

Cheers,

Matt

packers#1

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Re: New power for Metra, the SD70MACH
« Reply #22 on: October 13, 2022, 08:39:37 PM »
+1
Shouldn't the big question be - Why do you need a ~34 tonne axle load locomotive to haul around passenger cars on a suburban network?

Cheers,

Matt

Cheaper to reman a core than build new. Also probably cheaper still to reman a core nobody really wants versus a Geep.
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Pizzaparty

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Re: New power for Metra, the SD70MACH
« Reply #23 on: October 13, 2022, 10:23:43 PM »
+1
If they are pulling express trains their top speed has to be near the max in some stretches. Having been on them and standing on the platform when they went by they are hauling.

UP west lines (I’m familiar, I worked it for 4 months while borrowed out) is max 70 mph. Don’t forget you can regear them for passenger speeds too.

It’s just dollars and cents. The 710 prime mover is a very proven engine, EMD shops are close by, and there’s lots and lots of parts available for the next 20 years. And the SD70 family is a very proven family of locomotives as well

wcfn100

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Re: New power for Metra, the SD70MACH
« Reply #24 on: October 13, 2022, 10:30:36 PM »
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This doesn't seem right -

Quote
The remanufactured locomotives have a similar design to Metra’s F59 locomotives, so Metra will be able to use the same parts inventory and won’t need different training and maintenance programs.

This is from the https://metra.com/newsroom/new-metra-locomotive-debuts.

Jason

Bulbous

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Re: New power for Metra, the SD70MACH
« Reply #25 on: October 14, 2022, 02:09:20 AM »
+1
Cheaper to reman a core than build new. Also probably cheaper still to reman a core nobody really wants versus a Geep.

Thanks, makes some sense.

Still, one of my favourite locos of all time are the original 70MACs in BN Executive paint.

Cheers,

Matt

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Re: New power for Metra, the SD70MACH
« Reply #26 on: October 14, 2022, 08:41:32 AM »
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UP west lines (I’m familiar, I worked it for 4 months while borrowed out) is max 70 mph. Don’t forget you can regear them for passenger speeds too.

It’s just dollars and cents. The 710 prime mover is a very proven engine, EMD shops are close by, and there’s lots and lots of parts available for the next 20 years. And the SD70 family is a very proven family of locomotives as well

Also if they are over engineered for this role they should last much longer since they are never pushed to their limits. Especially if they were purchased at a great price point.
Brian

Way of the Zephyr

Hawghead

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Re: New power for Metra, the SD70MACH
« Reply #27 on: October 14, 2022, 11:42:21 AM »
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What is the max speed these will see in passenger service?  I've always seen a 75 mph limit on these locomotives.  I feel sorry for the engineers, these things ride like s$%t at speed.

Scott
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pedro

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Re: New power for Metra, the SD70MACH
« Reply #28 on: October 14, 2022, 02:16:05 PM »
+1
With the way the Metra schedule (speaking BNSF line here) was dumbed-down after PTC, top speed and acceleration is not terribly as important as it once was. On a local, we seldom get above 50 MPH between stops, sometimes less. Often you have to “dog it” between stops to keep from getting ahead of schedule. And an 11-car (our max length) express train is much heavier than you’d think; the gallery cars are 85 tons empty. It takes awhile to get one going 70 with a single F40. The schedule is pretty padded to absorb any minor delays.

pedro

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Re: New power for Metra, the SD70MACH
« Reply #29 on: October 14, 2022, 03:31:55 PM »
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I’m told the 70MACH are set up like the 400s where the HEP runs at notch 3 while in idle. I don’t recall the technicalities of how that works, but it’s better than the notch 8 all the time system.