Dominic Mazoch posted:

I hope they will not become "SDP70F's", and will not become wreck and rail breaker prone.

Again, you don't know what you are talking about! The old Amtrak SDP40F units didn't break any rails, and we only "derailment prone" on really crappy track, when coupled to a poorly maintained VERY light weigh Amtrak baggage car. Besides, the "70 Series" units have the Radial/steerable trucks anyway. 

  Also, will HEP come from the prime mover, or a secondary gen set?

Probably a separate inverter to provide HEP for the train.

 

pittsburghrailfan posted:

I'm a little confused. Presumably Progress/EMD will be retrofitting (probably) ex-BN SD70MACs with HEP generators a la the Alaska Railroad's SD70MACs.

Probably not, as simply adding a separate inverter to provide 480 Volt HEP, as has been done previously.

Why is the rendering of a SD70ACe?

Maybe the METRA folks don't know any better?

 

I’m a little confused by this decision. It’s clear that the idea was to go with cheap power and not spend a ton of money jumping on the Charger bandwagon, but why didn’t they purchase more F59PHRs and F59PHIs, or even more MP36PH-3Cs? Surely that would make more sense and be more efficient. They already have both of those locomotives which have proven themselves in service, so I don’t understand why they would go through all this trouble. I bet Hot Water knows something.

Dominic Mazoch posted:

I hope they will not become "SDP70F's", and will not become wreck and rail breaker prone.  Also, will HEP come from the prime mover, or a secondary gen set?

These SD70MAC-Hs won’t have that problem as the SDP40Fs were top-heavy due to poor weight distribution. There have been many successful 6-axle passenger units.

GenesisFan99 posted:
Dominic Mazoch posted:

I hope they will not become "SDP70F's", and will not become wreck and rail breaker prone.  Also, will HEP come from the prime mover, or a secondary gen set?

These SD70MAC-Hs won’t have that problem as the SDP40Fs were top-heavy due to poor weight distribution.

Where did you come up with such a ridiculous claim?

There have been many successful 6-axle passenger units.

 

GenesisFan99 posted:

I’m a little confused by this decision. It’s clear that the idea was to go with cheap power and not spend a ton of money jumping on the Charger bandwagon, but why didn’t they purchase more F59PHRs and F59PHIs, or even more MP36PH-3Cs?

Because EMD/Progress rail doesn't make 4 axle units anymore.

Surely that would make more sense and be more efficient. They already have both of those locomotives which have proven themselves in service, so I don’t understand why they would go through all this trouble.

Did you read the part of the press release concerning the trouble free AC traction motors vs. the old DC traction motors?

I bet Hot Water knows something.

 

GenesisFan99 posted:

I’m a little confused by this decision. It’s clear that the idea was to go with cheap power and not spend a ton of money jumping on the Charger bandwagon, but why didn’t they purchase more F59PHRs and F59PHIs, or even more MP36PH-3Cs? Surely that would make more sense and be more efficient. They already have both of those locomotives which have proven themselves in service, so I don’t understand why they would go through all this trouble. I bet Hot Water knows something.

Are F59's still being made?

Rusty

Rusty Traque posted:
GenesisFan99 posted:

I’m a little confused by this decision. It’s clear that the idea was to go with cheap power and not spend a ton of money jumping on the Charger bandwagon, but why didn’t they purchase more F59PHRs and F59PHIs, or even more MP36PH-3Cs? Surely that would make more sense and be more efficient. They already have both of those locomotives which have proven themselves in service, so I don’t understand why they would go through all this trouble. I bet Hot Water knows something.

Are F59's still being made?

Nope.

Rusty

 

Rusty Traque posted:
GenesisFan99 posted:

I’m a little confused by this decision. It’s clear that the idea was to go with cheap power and not spend a ton of money jumping on the Charger bandwagon, but why didn’t they purchase more F59PHRs and F59PHIs, or even more MP36PH-3Cs? Surely that would make more sense and be more efficient. They already have both of those locomotives which have proven themselves in service, so I don’t understand why they would go through all this trouble. I bet Hot Water knows something.

Are F59's still being made?

Rusty

They’re not, but neither are SD70MACs. That’s my point. They could easily have purchased more F59PHRs or F59PHIs to supplement their current fleet instead of buying SD70MACs. I understand the AC traction part, but why go through all the trouble of converting them when they could have just bought more of what they already have? 

Hot Water posted:
GenesisFan99 posted:
Dominic Mazoch posted:

I hope they will not become "SDP70F's", and will not become wreck and rail breaker prone.  Also, will HEP come from the prime mover, or a secondary gen set?

These SD70MAC-Hs won’t have that problem as the SDP40Fs were top-heavy due to poor weight distribution.

Where did you come up with such a ridiculous claim?

There have been many successful 6-axle passenger units.

 

See attached screenshot.

Attachments

Photos (1)

Well, whatever that is, I'm unable to read it. But then, if it's on the internet it MUST be true, right? The SDP40F units were NOT "top heavy", as the additional boiler water supply tank was mounted directly on the underframe, inside the carbody. When both the lower fuel & water tank plus the inside the carbody water tank were filled with water, the units total weight was close to 400,000 pounds, thus only certain railroads allowed Amtrak to utilize the carbody mounted water tank (there were supply valves, which were sealed, that would be opened for use on those railroads allowing the extra weight).

The bottom line was, you can't operate a heavy, i.e. over 395,000 pound locomotive, no mater whether freight or passenger, over crappy track, at passenger train speeds.

GenesisFan99 posted:
Rusty Traque posted:
GenesisFan99 posted:

I’m a little confused by this decision. It’s clear that the idea was to go with cheap power and not spend a ton of money jumping on the Charger bandwagon, but why didn’t they purchase more F59PHRs and F59PHIs, or even more MP36PH-3Cs? Surely that would make more sense and be more efficient. They already have both of those locomotives which have proven themselves in service, so I don’t understand why they would go through all this trouble. I bet Hot Water knows something.

Are F59's still being made?

Rusty

They’re not, but neither are SD70MACs. That’s my point. They could easily have purchased more F59PHRs or F59PHIs to supplement their current fleet instead of buying SD70MACs. I understand the AC traction part, but why go through all the trouble of converting them when they could have just bought more of what they already have? 

Like Hotwater mentioned, the AC traction was probably part of it. I also think there aren't that many F59PHIs or F59PHs on the used market right now. Metra bought their F59PHs (GO Transit) and F59PHis (Amtrak California and Cascades) because that was what was available, somewhat reliable, and cheapest at the time. The other operators of F59PH variants (AMT/Exo, Metrolink, Amtrak Piedmont, West Coast Express) are not currently selling their fleets (to my limited knowledge). MotivePower is offering the AC-traction, QSK95 powered MP54AC, but as noted above, new locomotives are expensive, and Metra seems to want EMD 710 engines that allow it to pay some lip service to reducing emissions and replace an aging fleet of F40 variants. I think Progress will use ex-BN SD70MACs because NS just returned several ex-BN executive livery leasers two months ago; I'm sure Progress is offering great financial terms to get rid of what was set to be for them an unproductive asset.

The F125s were supposed to replace the F59s on Metrolink, which have slowly been taken out of service. So it’s very likely that if there aren’t any units for sale now there certainly will be very soon. While I realize they want 710 engines, the 710 in the SD70MAC is not the same as the 710 in the F59PHRs and F59PHIs. 12-710G3C-ECs could be cannibalized and swapped between locomotives, instead of being slightly limited in the parts they can share.

Hot Water posted:

Well, whatever that is, I'm unable to read it. But then, if it's on the internet it MUST be true, right? The SDP40F units were NOT "top heavy", as the additional boiler water supply tank was mounted directly on the underframe, inside the carbody. When both the lower fuel & water tank plus the inside the carbody water tank were filled with water, the units total weight was close to 400,000 pounds, thus only certain railroads allowed Amtrak to utilize the carbody mounted water tank (there were supply valves, which were sealed, that would be opened for use on those railroads allowing the extra weight).

The bottom line was, you can't operate a heavy, i.e. over 395,000 pound locomotive, no mater whether freight or passenger, over crappy track, at passenger train speeds.

According to the NTSB reports I read for SDP40F derailments since the internet isn’t valid info, the track was up to standard at the time so the track wasn’t crappy. I wouldn’t exactly call 40-50 mph “passenger train speeds”.

Just for the record, we never had a track/train dynamics derailment of an SDP40F on Santa Fe, and we ran them long distances, fast. We even bought a group of them from Amtrak and re-fitted them for freight service.  No problems at all.  And I did not get this information from reading railfan magazines.  I was there.

It sounds to me like Metra is going to be getting a good deal on good locomotives.

Tom

 

Superintendent, High Plains Division (O Gauge) 

The Panhandle & Santa Fe Railway Co.

Lone Star Hi-Railers

Santa Fe, All the Way

Road on SDP40F powered passenger trains.  LONE STAR.  SW LTD./CHIEF.  SAN FRANCISCO ZYPHER over Sherman Hill.  Clocked mile post to mile post.  36 seconds.  100 mph.  But that was on ATSF and original UP.  Good track

The TEXAS SPECIAL:  The REAL RED streak of the golden prairies!

From what I understand, the SDP40Fs were only set up to do 95 mph so not sure how they would hit 100.

Anyway I’ve done some further reading and it seems like Metra really didn’t have any other options. Apparently Metrolink’s F59PH fleet has to have their engine blocks destroyed as part of the provisions for the grant that gave them funding for their F125s, and the lease/for sale fleet is a lot more limited than previously thought. To be clear-I wasn’t against the idea because they were six axle units, was just against it because it would have made more sense and been more efficient to buy more of what they already had if it was available (which it apparently wasn’t). SD70MACs definitely wouldn’t have been my first choice if it was my decision to make, but if they’re ex-BN units they’ll at least be pretty reliable.  Will be very interesting to see these in service.

GenesisFan99 posted:

From what I understand, the SDP40Fs were only set up to do 95 mph so not sure how they would hit 100.

Looks like you "understand" incorrectly. They were good for at least 102 MPH on the Santa Fe.

Anyway I’ve done some further reading and it seems like Metra really didn’t have any other options. Apparently Metrolink’s F59PH fleet has to have their engine blocks destroyed

All that was done was a whole was drilled someplace in the crankcase (EMD two-stroke engines do NOT have "blocks", as the crankcase is a welded/fabricated assembly). Thus, that hole can easily be welder up.

as part of the provisions for the grant that gave them funding for their F125s, and the lease/for sale fleet is a lot more limited than previously thought. To be clear-I wasn’t against the idea because they were six axle units, was just against it because it would have made more sense and been more efficient to buy more of what they already had if it was available (which it apparently wasn’t).

That, of course, is only your opinion.

SD70MACs definitely wouldn’t have been my first choice if it was my decision to make,

So,,,,,,you have a wealth of Mechanical Engineering experience in the field of railroad motive power and associated interchangeability and reliability?

but if they’re ex-BN units they’ll at least be pretty reliable.  Will be very interesting to see these in service.

Same here, as I hope they will be passing through our town, on the former Burlington 3 track main line. I'm sure my good friend, who left EMD and now is a manager at METRA, will keep me updated on these units, since I spent so much time with the SD70MAC units on the BN, out in the Wyoming Powder River Basin coal fields (1991 thru 1998), prior to my retirement.

 

Well at least the SD70MACs will be back at home on the "race track". I remember them on coal trains as a kid. Lately it's been mostly GEs on everything, with the occasional SD70ACE. Although I'll miss the slanty nose FP40s.

Santa Fe, All the Way

Lou1985 posted:

Well at least the SD70MACs will be back at home on the "race track".

For what it's worth, the term "race track" is a rail enthusiast term. The CB&Q/BN/BNSF people refer to it as "The East End".

I remember them on coal trains as a kid. Lately it's been mostly GEs on everything, with the occasional SD70ACE. Although I'll miss the slanty nose FP40s.

 

Hot Water posted:
Lou1985 posted:

Well at least the SD70MACs will be back at home on the "race track".

For what it's worth, the term "race track" is a rail enthusiast term. The CB&Q/BN/BNSF people refer to it as "The East End".

I remember them on coal trains as a kid. Lately it's been mostly GEs on everything, with the occasional SD70ACE. Although I'll miss the slanty nose FP40s.

 

Oh I know. I just figured more people would recognize the layman's term.

Santa Fe, All the Way

Based on what choices they likely had, I'd say it's an EXCELLENT choice.  AC traction, radial trucks, a track record of being used in passenger service (Alaska) and the fact that should they chose to do so, there are a couple of nice rebuild programs available out there that could bring these locomotives into the 21st century.  With proper care, I'd be willing to bet they will outlive those fancy "door stop" passenger units they bought.  I always thought they should have took their F40Cs and sent them through an SD32ECO rebuild program and kept using them.

Hot Water posted:
 

......since I spent so much time with the SD70MAC units on the BN, out in the Wyoming Powder River Basin coal fields (1991 thru 1998), prior to my retirement.

 

If you would indulge us please, of your opinion on the SD70MAC units overall. I have always been a modern diesel fan and not experienced with real trains. It is always good to read an experienced RR person's inside info. I feel that these units were the pivotal units leading the AC trend that seemed to take over now.

 Having no practical experience only leaves me to read up on what I can get my hands on. I haven't seen much comparisons of say the SD70MAC to the SD70M units for example. I have read some general comparisons to the GE's of the same time frame.

" on Sour mash and cheap wine " ??

Why go back to DCC when I have DCS!

Engineer-Joe posted:
Hot Water posted:

......since I spent so much time with the SD70MAC units on the BN, out in the Wyoming Powder River Basin coal fields (1991 thru 1998), prior to my retirement.

If you would indulge us please, of your opinion on the SD70MAC units overall. I have always been a modern diesel fan and not experienced with real trains. It is always good to read an experienced RR person's inside info. I feel that these units were the pivotal units leading the AC trend that seemed to take over now.

Joe,

During my 36 1/2 year career with EMD (June 1 1962 thru December 24, 1998) I always felt that the SD40-2/SD45-2 were the best units I ever worked with. Until the SD70MAC units! Sure the new new "MACs" had the typical "new design" bugs, especially the KNOR Electronic Airbrake system, but once the Semens people from Germany understood the unbelievable temperature extremes that the AC Inverters and their own computers had to work with, i.e. a coal train be loaded in the Powder River Basin of Wyoming at temps as cold as -35 degrees F, proceed to Houston Texas area, and unload the coal at 85 degrees F with 90% humidity, all within 3 days running time, the units became VERY reliable.

In training the various Engineers and Road Foremen out of the Gillette, WY terminal, it quickly became apparent that a pair of SD70MAC units on the headend of 18,000 tons of coal, with another DPU SD70MAC on the rear, you could almost defy the laws of physics on the BN/BNSF Orin Subdivision. During the occasional "hot day", if the inverters got hot enough, they would automatically power-limit, and you would stall on the ascending grade. No problem; simply apply the train air brakes and stop, place the units in "neutral" and Reve the engines up to blow cooling air through the traction inverters. After about 10 or 15 minutes, you could call up the inverter temperature screen on the computer, and make sure that they had cooled down to "normal".

Then, with the air brakes still set, place the rear DPU in forward throttle 6, and the lead units in forward throttle 6, thus straining against the train, so then when the air brakes are released, the train will NOT roll backwards. As the brakes release, the rear DPU is placed in throttle 8, and the lead units placed in throttle 7. Still holding the independent brakes on, when the train is fully released and the rear DPU begins pushing in any slack, ease down the independent brakes to about 30 psi, and place the lead units in throttle 8. Ever so gradually the train begins to move forward up the grade, as the Engineer lowers the independent brake down to about 10 pis, they all the way off. There is no wheel slip, and the train slowly accelerates up the grade to about the balance speed of 10 to 15 MPH.

Such action with DC traction SD40/SD40-2 units would pretty much destroyed all the DC traction motors, by causing massive stall burns on the copper commutators. No problem for an AC traction SD70MAC!

 Having no practical experience only leaves me to read up on what I can get my hands on. I haven't seen much comparisons of say the SD70MAC to the SD70M units for example.

The SD70MAC units are AC traction, while the SD70 is DC traction.

I have read some general comparisons to the GE's of the same time frame.

 

Interesting thread, especially Jack's notes above...

My understanding of the Alaska RR SD70MACs in passenger service (4300-series) is that internal switching disconnects the rear traction inverter from the rear truck traction motors and this inverter then provides 480V 3-phase HEP to the train. This locomotive then has just its forward truck powered, so ARR usually has a second unit in the consist to provide adequate traction for the train. When the unit is in freight service, or another HEP source is available, then all six axles are powered.

I am wondering if the METRA SD70MACs will be the same, or if they found a way to squeeze in an additional inverter for the HEP while keeping all traction motors operative?  

The GN Man posted:

Interesting thread, especially Jack's notes above...

My understanding of the Alaska RR SD70MACs in passenger service (4300-series) is that internal switching disconnects the rear traction inverter from the rear truck traction motors and this inverter then provides 480V 3-phase HEP to the train. This locomotive then has just its forward truck powered, so ARR usually has a second unit in the consist to provide adequate traction for the train. When the unit is in freight service, or another HEP source is available, then all six axles are powered.

I am wondering if the METRA SD70MACs will be the same, or if they found a way to squeeze in an additional inverter for the HEP while keeping all traction motors operative?  

According to what I've read elsewhere, this "new", i.e. completely re-manufactured units, will have 6 inverters: 4 for traction (there would thus be only 4 AC traction motors), and 2 for HEP. 

EMD posted:

Any idea if these units will have desktop or traditional controls?

Since the former BN/BNSF SD70MAC units do have the full width nose and "super cab" with the desk-top control arrangement, one would assume that these re-manufactured units would retain that arrangement.

HW, does EMD still have the SD60MACs?

I have no idea what happened to them.

 

EMD posted:

Any idea if these units will have desktop or traditional controls?

HW, does EMD still have the SD60MACs?

EMD converted them to test beds a few years back like the NS100/CRQ1. On a side not, hopefully Athearn makes these units in HO as I would almost definitely get one or two.

Hot Water posted:
Dominic Mazoch posted:

And how fast will these locomotives have to go in commuter service?  My guess is they will need to go much faster than passenger trains on the Alaska.

I would think that they should be capable of at least 75 MPH.

They will likely be geared for passenger service rather than freight, giving them a higher top speed. The gearing for passenger locomotives reduces the overall tractive effort for heavy loads but increases the acceleration rate from a standstill as well as giving the higher top speed...

I wish NJT would consider these engines in the future!

Tom

New to O scale....

Krieglok posted:
Hot Water posted:
Dominic Mazoch posted:

And how fast will these locomotives have to go in commuter service?  My guess is they will need to go much faster than passenger trains on the Alaska.

I would think that they should be capable of at least 75 MPH.

They will likely be geared for passenger service rather than freight, giving them a higher top speed. The gearing for passenger locomotives reduces the overall tractive effort for heavy loads but increases the acceleration rate from a standstill as well as giving the higher top speed...

I wish NJT would consider these engines in the future!

Tom

For what it's worth, the BN/BNSF SD70MAC units were already "geared" for 70MPH with the overspeed set for about 72 in the speed-control system. Unlike a DC traction motor, with its copper commutator bars that are subject to damage from high centrifugal forces, the AC three phase induction tractor motor rotor is not seriously affected by centrifugal forces.

Dieselbob posted:

How fast do Metra trains actually run? 

I believe it depends on the line, i.e. UP or BNSF for example, but they have lots of 79 MPH speed limit areas.

The couple that I have rode didn't really ever get up that much speed, but we were not going very far out of downtown.

I'm pretty sure that the express trains that METRA runs on the BNSF line we live on, operate over 70 MPH.

 

Hot Water posted:
Dieselbob posted:

How fast do Metra trains actually run? 

I believe it depends on the line, i.e. UP or BNSF for example, but they have lots of 79 MPH speed limit areas.

The couple that I have rode didn't really ever get up that much speed, but we were not going very far out of downtown.

I'm pretty sure that the express trains that METRA runs on the BNSF line we live on, operate over 70 MPH.

 

I'd have to clock one but the BNSF line express trains I've seen appear to be doing close to the 79mph limit at times, along with some west cost bound Amtrak trains. But La Grange/Brookfield have a lot of buildings around the tracks, making it harder to judge speed without measuring. Not like BNSF doesn't run intermodal trains at a good clip through the area.

When the SD70MACs were produced what was their top speed? I though I remember an article from the early 90's in Trains magazine saying they topped out around 70 mph, but I'm probably way off.

Santa Fe, All the Way

Lou1985 posted:
Hot Water posted:
Dieselbob posted:

How fast do Metra trains actually run? 

I believe it depends on the line, i.e. UP or BNSF for example, but they have lots of 79 MPH speed limit areas.

The couple that I have rode didn't really ever get up that much speed, but we were not going very far out of downtown.

I'm pretty sure that the express trains that METRA runs on the BNSF line we live on, operate over 70 MPH.

 

I'd have to clock one but the BNSF line express trains I've seen appear to be doing close to the 79mph limit at times, along with some west cost bound Amtrak trains. But La Grange/Brookfield have a lot of buildings around the tracks, making it harder to judge speed without measuring. Not like BNSF doesn't run intermodal trains at a good clip through the area.

I am currently trying to find out what the maximum speeds are for METRA trains on the BNSF and UP lines.

When the SD70MACs were produced what was their top speed?

The BN had the speedometer overspeed trips set for about 72 MPH. Naturally the maximum speed was never reached on loaded or empty coal/hopper trains. If and when they were ever assigned to intermodal trains (very rarely), the could run 70 MPH.

I though I remember an article from the early 90's in Trains magazine saying they topped out around 70 mph, but I'm probably way off.

No, you are correct.

 

Hot Water posted:
Lou1985 posted:
Hot Water posted:
Dieselbob posted:

How fast do Metra trains actually run? 

I believe it depends on the line, i.e. UP or BNSF for example, but they have lots of 79 MPH speed limit areas.

The couple that I have rode didn't really ever get up that much speed, but we were not going very far out of downtown.

I'm pretty sure that the express trains that METRA runs on the BNSF line we live on, operate over 70 MPH.

 

I'd have to clock one but the BNSF line express trains I've seen appear to be doing close to the 79mph limit at times, along with some west cost bound Amtrak trains. But La Grange/Brookfield have a lot of buildings around the tracks, making it harder to judge speed without measuring. Not like BNSF doesn't run intermodal trains at a good clip through the area.

I am currently trying to find out what the maximum speeds are for METRA trains on the BNSF and UP lines.

When the SD70MACs were produced what was their top speed?

The BN had the speedometer overspeed trips set for about 72 MPH. Naturally the maximum speed was never reached on loaded or empty coal/hopper trains. If and when they were ever assigned to intermodal trains (very rarely), the could run 70 MPH.

I though I remember an article from the early 90's in Trains magazine saying they topped out around 70 mph, but I'm probably way off.

No, you are correct.

 

Huh. I remembered something accurately for once.

If you find the max speed on BNSF/UP let us know. Otherwise next time I'm in downtown La Grange I'll try clocking an express train.

Santa Fe, All the Way

Hot Water posted:
Lou1985 posted:

Otherwise next time I'm in downtown La Grange I'll try clocking an express train.

Without a pretty accurate radar gun, how would you plan on doing THAT?

 

 

The old fashioned way. Time it takes to travel a set distance. Although a radar gun or laser timers would be much more accurate.

Santa Fe, All the Way

OK, latest information from METRA:

1) On BNSF and UP lines, the speedometer overspeed is set at 72 MPH, as both railroad's maximum speed for METRA is 70 MPH.

2) The Milwaukee Road and Rock Island lines, the overspeed is set at 82 MPH, as the max speed for METRA is 79 MPH.

Hot Water posted:
The GN Man posted:

Interesting thread, especially Jack's notes above...

My understanding of the Alaska RR SD70MACs in passenger service (4300-series) is that internal switching disconnects the rear traction inverter from the rear truck traction motors and this inverter then provides 480V 3-phase HEP to the train. This locomotive then has just its forward truck powered, so ARR usually has a second unit in the consist to provide adequate traction for the train. When the unit is in freight service, or another HEP source is available, then all six axles are powered.

I am wondering if the METRA SD70MACs will be the same, or if they found a way to squeeze in an additional inverter for the HEP while keeping all traction motors operative?  

According to what I've read elsewhere, this "new", i.e. completely re-manufactured units, will have 6 inverters: 4 for traction (there would thus be only 4 AC traction motors), and 2 for HEP. 

Soooo,  maybe they are becoming like the current C4 variants (either A1A or B1)?

And METRA stipulated in the article they will meet Tier III requirements.

rdunniii posted:
Hot Water posted:
The GN Man posted:

Interesting thread, especially Jack's notes above...

My understanding of the Alaska RR SD70MACs in passenger service (4300-series) is that internal switching disconnects the rear traction inverter from the rear truck traction motors and this inverter then provides 480V 3-phase HEP to the train. This locomotive then has just its forward truck powered, so ARR usually has a second unit in the consist to provide adequate traction for the train. When the unit is in freight service, or another HEP source is available, then all six axles are powered.

I am wondering if the METRA SD70MACs will be the same, or if they found a way to squeeze in an additional inverter for the HEP while keeping all traction motors operative?  

According to what I've read elsewhere, this "new", i.e. completely re-manufactured units, will have 6 inverters: 4 for traction (there would thus be only 4 AC traction motors), and 2 for HEP. 

Soooo,  maybe they are becoming like the current C4 variants (either A1A or B1)?

And METRA stipulated in the article they will meet Tier III requirements.

Since the trucks are 3 axle, the traction motors will be mounted on the first 2 axles within each truck, providing an AAR powered wheel arrangement of A-A-1  1-A-A. Remember that E Units were A-1-A  A-1-A, with the unpowered "idler" in the center position. With the HTC-R "Radial" truck, the "idler" will be on the end, or inboard position.

Krieglok posted:
Hot Water posted:
Dominic Mazoch posted:

And how fast will these locomotives have to go in commuter service?  My guess is they will need to go much faster than passenger trains on the Alaska.

I would think that they should be capable of at least 75 MPH.

They will likely be geared for passenger service rather than freight, giving them a higher top speed. The gearing for passenger locomotives reduces the overall tractive effort for heavy loads but increases the acceleration rate from a standstill as well as giving the higher top speed...

I wish NJT would consider these engines in the future!

Tom

For commuter service?  Passenger gearing?  The SD70MAC's have been routinely operating on BNSF at 70 MPH on coal trains and other freight trains on former ATSF territory.  Does METRA operate commuter trains faster than 70 MPH?  And, if so, do the longer, heavier, commuter trains actually have enough time to get up to 75 or 79 MPH between stops and can METRA trains achieve and maintain a speed in excess of 70 MPH for long enough to make any real difference in the schedules?  70 MPH=51 seconds/mile.  75 MPH=48 seconds/mile.  79 MPH= 45 seconds/mile*.  So, as opposed to using a 70 MPH gearing, to shave a minute of running time between stops at 75 MPH, the train has to operate at 75 MPH for 20 miles.  To shave a minute of running time between stops at 79 MPH, the train has to operate at 79 MPH for 11.3 miles.  While speeds above 70 MPH are certainly beneficial to the schedules of most inter-city passenger trains, the shorter distances between stops in commuter service eat up much of the higher speed advantage with the reduced amount of time available to maintain higher speeds.  Also, if a train has to reduce for curves or - worse - to proceed through crossovers (as when weaving through traffic or running around a slower, non-express train), the higher speed advantage is reduced or eliminated.

I'm not saying that there would be any significant additional cost in the rebuilding process (none at all if new ring and pinion gears are specified as part of rebuilding).  I am only questioning whether passenger gear ratios are useful for METRA service, because their purpose is to allow running time to be reduced by maintaining higher speed.

*  These speed/time equations are slightly rounded to avoid using fractions of seconds.  The equations, as presented, are the accepted standard for measuring speed between mile posts.

Tom

 

Superintendent, High Plains Division (O Gauge) 

The Panhandle & Santa Fe Railway Co.

Lone Star Hi-Railers

Santa Fe, All the Way

To re-emphasize what Tom just posted above, the BN/BNSF SD70MAC units, having AC three phase induction traction motors, are NOT affected by higher RPM rotor speeds (they do NOT have the copper bar commutator as DC motors have). More than one SD70MAC unit was fully tested at the AAR Test Center, out in Colorado, and was also operated on the "Fast Track" at speeds up to 100 MPH. Nothing flew apart!

Dominic Mazoch posted:

Advantage of the A-A-1 traction motor arrangement for the AC truck vs A-1-A for the E units?

Completely different truck designs. The old/original Blomberg A-1-A truck (yes, the same Mr. Blomberg that later designed the famous 2 axle truck with 40" diameter wheels for the FT units) had only 36" diameter wheels. The HTC-R "Radial" truck is far superior, and due to its "steerable" design reduces flange contact/wear on curves, not to mention far superior adhesion for high traction situations.

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