Discussion related to commuter rail and rapid transit operations in the Chicago area including the South Shore Line, Metra Rail, and Chicago Transit Authority.

Moderators: JamesT4, metraRI

  by eolesen
 
Inverter technology has evolved a bit. There's room for three inverters in the SD70MACH, so they won't need to go with only three axles.

A third inverter allows them to use two for truck power in an A-1-A arrangement, just like the E8/E9's, and the third inverter to HEP.
  by RRspatch
 
eolesen wrote:
It's a fact. EMD has offered inverter based HEP as an option for the past 10 years. ARR is definitely using it. I'm not sure why UP hasn't wound up with a few that can be used with their Heritage fleet. Having a dozen or two for executive and engineering specials would be a lot more flexible and probably cheaper than the dedicated power cars.
Lets see here, you're trying to compare the ARR which basically has one line from Anchorage to Fairbanks with the UPRR which has lines all over the western US. Union Pacific power is spread out all over the western US. Trying to keep a hand full of HEP equipped units near Council Bluffs where the business and excursion trains are kept isn't a good use of equipment nor very practical. Locomotives earn their keep pulling trains not waiting around Council Bluffs for the rare business car special or steam excursion. In the case of the UPRR power cars work better as to allow anything from a GEVO to a Big Boy to full the train.
  by mtuandrew
 
eolesen wrote:Inverter technology has evolved a bit. There's room for three inverters in the SD70MACH, so they won't need to go with only three axles.

A third inverter allows them to use two for truck power in an A-1-A arrangement, just like the E8/E9's, and the third inverter to HEP.
Wonder if they’ll keep the two power + one HEP inverter solution, or will move to the six power inverter (with one part-time devoted to HEP). Realistically, there’s enough space for a HEP sled too if Metra would prefer for some reason.
  by Fan Railer
 
I will say again, the SD70MAC-H will have inverter driven HEP like the Alaska RR SD70s do. If you go onto Metra's website and find the board meeting video pertaining to this procurement, you will see the presentation powerpoint that states as much.

The reasoning behind this is due to the redundant capabilities of inverter-HEP when running an AC powered locomotive. The MAC-H will have one traction inverter per axle, so if the HEP inverter fails, one of the 6 traction inverters can be re-purposed for HEP supply with minimal loss in traction power.

Remember we're in 2019, not 2004. No one builds AC traction locomotives without individual axle control anymore. Each traction motor will have its own inverter.
Last edited by Fan Railer on Thu Feb 28, 2019 8:34 pm, edited 1 time in total.
  by Backshophoss
 
The MP-36's had their HEP inverters tossed out for Gen-set HEP pallets, the bid spec allows for both options,
METRA seems to prefer HEP gen-sets to allow prime mover shutdowns,all the F-59's are gen-set HEP,stands to reason
the easy option is to fit a Gen-set HEP over a total rewire of the loco to add an inverter and allow transfer of HEP supply
between a traction motor inverter/HEP supply inverter.
  by eolesen
 
How hard is it for people to accept the fact that these won't have genset HEP?.....

The F59's came as-is from Amtrak. The SD70MACH's will come from rebuild.
  by Fan Railer
 
eolesen wrote:How hard is it for people to accept the fact that these won't have genset HEP?.....

The F59's came as-is from Amtrak. The SD70MACH's will come from rebuild.
I think people are also forgetting that most SD70MACs have an as-built weight of 415,000 lbs. Assuming an upper limit of 432,000 lbs, that doesn't leave a lot of wiggle room to work with in terms of adding in an ENTIRE genset skid (diesel engine, alternator, associated framing and electrical wiring, fuel lines, exhaust manifolds, etc). They're already being rebuilt with Tier III 16-710s, which comes with additional cooling systems, so you've already lost some of the 17k lbs wiggle room you started with. And that doesn't even consider the question of where within the locomotive you'd fit such a skid without lengthening the body 4-6 feet: https://web.archive.org/web/20041114163 ... MAC_EN.pdf" onclick="window.open(this.href);return false;
  by eolesen
 
There could be more wiggle room if the fuel tank is reduced from 5000 gals down to 1500 or 2000 (the F40PH's came with a 1500 capacity).

A 3,000 gal fuel reduction should take off around 18,000 lbs, plus the steel is probably another 2,000 lbs.
  by Fan Railer
 
eolesen wrote:There could be more wiggle room if the fuel tank is reduced from 5000 gals down to 1500 or 2000 (the F40PH's came with a 1500 capacity).

A 3,000 gal fuel reduction should take off around 18,000 lbs, plus the steel is probably another 2,000 lbs.
Even if you reduced the fuel tank size, you're pretty short on internal space inside the existing locomotive body. I doubt even adding another 6 feet would create enough space for a genset skid.
  by Gilbert B Norman
 
Tadman wrote: ....not so at Milwaukee
Mr. Dunville, I had "just hired on" at the MILW when the decision was made to operate FP-45's as trailing units only in psssenger service. On A-Day, "we" withheld those units from Amtrak, knowing the potential for "problems" over the road, let alone if they operated over a foreign road (remember, on A-Day, the roads assumed liability for "anything and everything").
  by Tadman
 
I have heard of such practice, and I'm curious if it was related to mechanical issues or ride quality. Either way, methinks the Milwaukee had rotten tracks, as the SP and Santa Fe had great luck with FP45 and SDP45.
  by eolesen
 
Fan Railer wrote: Even if you reduced the fuel tank size, you're pretty short on internal space inside the existing locomotive body. I doubt even adding another 6 feet would create enough space for a genset skid.
It's established fact they're using inverters. Period. There. Will. Not. Be, Genset. Head. End. Power.

Entertaining that any further is a waste of screen pixels.

My comment on the hypothetical reduction in fuel capacity is targeted at the overall weight of the locomotive vs. the other types currently in use.
  by Alcochaser
 
Well I listened to the guy speak.
From the way he talked. These will essentially be new Tier 3 SD70MAC Inverter HEP.
Now from the way he talked, these will be Six inverter locomotive. Under HEP five axles powered, one idle.

These might not even be from current SD70MACs. Progress/EMD holds title to a bunch of ex ATSF/BNSF SD75M and SD75I which would make GREAT rebuild candidates.

Sounds like these will be like the NS SD70ACC but using one of the traction inverters for HEP. Leaving five for traction.