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 Tadman
 
https://metrarail.com/about-metra/newsr ... e-purchase" onclick="window.open(this.href);return false;

In a move that reeks of common sense usually not displayed at a public railroad, Metra is buying 15 rebuilt SD70MAC with HEP added during the rebuild.
  by eolesen
 
Such a great move. Will they be four axle or six?....
  by Backshophoss
 
SD 70MACH's are 6 axle power. They have AC traction motors and alternator
  by CHTT1
 
Rebuilding a bunch of old freight locomotives? I suppose it's better than having the current fleet break down, but it's only a stop gap measure. Time to get a transportation funding bill going in Illinois.
  by Gilbert B Norman
 
Sources such as WBBM 780 and TRAINS Newswire report that METRA will acquire 15 rebuilt EMD SD-70 locomotives.

These locomotives are mounted on six-wheeled trucks.

Uh, isn't passenger engines on six wheeled trucks a "been there, done that" with "uh, not exactly" stellar results?

Oh I suppose they could "get by" where there are long tangents, e.g. BNSF, MD-N, elsewhere ??????
  by Backshophoss
 
METRA seems more comfortable buying used instead of new,and feel they get a better bang for the buck then ordering new and
dealing with the teething problems of new power.
ALSO the SD70MAC's and the F59's share a lot of parts including the HEP genset pallets
  by Fan Railer
 
HEP Genset pallets will be irrelevant here, since the SD70MAC-H will be using an inverter driven HEP setup.
  by Tadman
 
Fan Railer wrote:HEP Genset pallets will be irrelevant here, since the SD70MAC-H will be using an inverter driven HEP setup.
Do we know that for a fact? I don't know either way, but I think they've been especially vague on a few things like that.
  by Tadman
 
Gilbert B Norman wrote:Uh, isn't passenger engines on six wheeled trucks a "been there, done that" with "uh, not exactly" stellar results?
Controlling for the variables, the results were great. Metra was fine with their F40C's for 30 years. Quite a few passenger carriers ran the SDP35/40/45 and U34CH with no problems, including Santa Fe, Great Northern, Southern Pacific, Erie Lackawanna, and Seaboard. The FP45 worked great at Santa Fe, not so at Milwaukee.

The only real problem areas were the SDP40f and the U28/30CG. Given that the FP45 and U34CH were very similar, I'd say it's down to other variables and not the presence of six axles.
  by chrisf
 
Tadman wrote: Do we know that for a fact? I don't know either way, but I think they've been especially vague on a few things like that.
Alaska Railroad already has factory built HEP equipped SD70MACs which use one of the traction inverters to generate HEP. They apparently only have either 3 or 4 traction motors online when HEP is engaged. It seems likely these Metra units will be similar.
  by Backshophoss
 
METRA swapped out the HEP inverters on the MP-36's to a gen-set HEP,to save the prime mover on those units,
considering the lack of fresh air at CUS,METRA prefers separate gen-set HEP. :wink:
  by eolesen
 
Tadman wrote:
Fan Railer wrote:HEP Genset pallets will be irrelevant here, since the SD70MAC-H will be using an inverter driven HEP setup.
Do we know that for a fact? I don't know either way, but I think they've been especially vague on a few things like that.
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.
  by Alcochaser
 
How they are going to add the HEP will be curious.

It is important to note that the Alaska RR SD70MAC with HEP disconnect one of the two trucks in HEP mode.
And SD70MAC has two inverters. One for each truck. The EMD solution was to divert one of the two traction inverters to the HEP. So in HEP mode the ARR units are 3 axles powered ONLY. On the ARR it is not a big deal as they double head the passenger trains. So 1.5 SD70MACs are plenty enough to pull ARR's trains.

I don't think your going to get away with this trick on Metra.

Also passenger gear-sets have NEVER been made for these. Now because the AC motors you can run the motors a faster speed then normal. But you top out at 75MPH or 80MPH depending. Probably not an issue for Metra. But your going to be operating near the motors max speed a lot.

However, these things will pull a BIG load. Asuming they come up with HEP solution that doesn't disconnect a truck, these will never need double headed even on the LARGEST trains.

Plus... Maybe Metra can sell it's switcher fleet? The SD70MACs can do that job too.
  by chrisf
 
Alcochaser wrote:How they are going to add the HEP will be curious.

It is important to note that the Alaska RR SD70MAC with HEP disconnect one of the two trucks in HEP mode.
And SD70MAC has two inverters. One for each truck. The EMD solution was to divert one of the two traction inverters to the HEP. So in HEP mode the ARR units are 3 axles powered ONLY. On the ARR it is not a big deal as they double head the passenger trains. So 1.5 SD70MACs are plenty enough to pull ARR's trains.
Running the SD70MAC with only 3 powered axles all the time would seem to be a bit strange, but based on these pages:
https://www.thedieselshop.us/Data%20EMD%20SD70MAC.HTML" onclick="window.open(this.href);return false;
https://www.thedieselshop.us/Data%20EMD%20F40PH.HTML" onclick="window.open(this.href);return false;
An SD70MAC provides far more than double the tractive effort of an F40PH. Half an SD70MAC should still offer some performance improvement.