Differences between the Milwaukee Road's two electrified divisions

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Differences between the Milwaukee Road's two electrified divisions
Posted by Rails West on Friday, December 31, 2010 2:04 AM

As most here know, the Milwaukee Road had two electrified divisions on its western mainline:  a 440-mile division in the Rocky Mountains, and a 227-mile portion on its Coast Division. 

I've always wondered, what were some of the key differences between the two electrified divisions?  For instance, was one division generally more successful than the other?  Was one more efficient?  Did one division save or cost the railroad more money than the other?

To start things off, according to a book I am reading, in the first 5 or so years of operation, the Rocky Mountain electrification gave the railroad a better operating savings over steam than the Coast electrification.  The reason for that is because the Coast division cost the company about twice as much per mile to electrify than the Rocky Mountain division.

The Rocky Mountain electrification was completed in 1917, and the Coast portion was started later and completed in 1920.  Unfortunately, war-time inflation hit during the construction of the Coast portion, driving prices way up.  Here is how those higher costs impacted operating savings on the Coast division:

On the Rocky Mountain division, operating savings from the electrification vs. steam operations amounted to 21% per year for the first 8-1/2 years.  Which after a 5% bond interest was paid, gave a net return of 21% - 5% = 16%.

But on the Coast electrification, because of the higher construction costs, operating savings amounted to only 7.5%.  And after bond interest of 6%, net return was only 7.5% - 6% = 1.5%.

That figure of 1.5% suggests to me that the investment in the Coast electrification was barely above the break-even mark.  So, the Rocky Mountain electrification appears to have been a much better investment, at least right in the first few years of operation.

Are there any other interesting differences between the two electrified divisions?

- Rails West

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Posted by erikem on Friday, December 31, 2010 12:23 PM

Winters on the Rocky Mountain divisions were much colder than the Coast divisions. Steam locomotives performance degrades with really cold weather (performance drop can be 30%), and the cost of maintaining water supply also increases as the temperature drops.

The Rocky Mountain division had 6 major grades, two for the Belt mountains, two for the Continental Divide and two for the Bitterroots. The Coast Division had three major grades, EB for the Cascades and two for the Saddlebacks. The most severe grade on the whole Puget Sound Extension was the 2.2% WB to the Saddlebacks.

The Coast division had shorter spacing between substations, presumably to reduce copper needed for the feeders. Substations for the Rocky Mountain divisions each had a "spare" M-G set (for 1917 requirements), where the Coast division substations were equipped only for 1920 era requirements. This is likely the reason that the Milwaukee kept the Joe's on the Rocky Mountain section.

The Milwaukee did have plans from the beginning to electrify the freight line between Avery and Othello from the beginning, but the combination of inflation and the Milwaukee's worsening financial condition kept those plans from reaching fruition. The last extension of the electrification was from Black River Junction to Seattle and this was to eliminate the need for a steam locomotive to haul passenger trains the 10 miles from the junction to Seattle.

I think you nailed it in attributing inflation as a chief cause of the difference in the rate of return. This was one of innumerable situations where WW1 caused inflation adversely affected the RR's (and transit).

- Erik

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Posted by PNWRMNM on Friday, December 31, 2010 1:37 PM

Erik,

I grew up in Eastern Washington.  I know of no "saddlebacks".  The MILW did climb the flanks of the Saddle Mountains between the Columbia River and Boylston.  IIRC the ruling grade was 2.2% westward and 1.6% eastward.  Boylston summit was very near as high as Snoqualmie summit.

Mac McCulloch

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Posted by erikem on Friday, December 31, 2010 9:34 PM

Mac,

Never thought I had a perfect memory, and thanks for the correction. You do recall correctly in that the WB grade is 2.2% and also recall correctly that EB grade is 1.6%. FWIW, the maximum gradient between Ellensburg and Snoqualmie summit was 0.7%. Boylston summit was about 100 feet lower than Snoqualmie summit.

Towards the later years of the electrification, the Milwaukee was running some heavy WB trains using two EF-5's, they had to run in full series to keep from overloading the substations and thus would take two hours to climb the hill. If the substations and overhead were set up to allow two sets of EF-5's to run in parallel, the climb would have been within the hourly rating of the motors and the trains could have been 30% heavier.

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Posted by Rails West on Saturday, January 1, 2011 12:40 AM

That was interesting about double sets of 4-unit boxcabs (class EF-5's) on one train.

Out of curiosity, I looked up some power information on that locomotive combination.  Per Holley, one EF-5 was rated 6680 hp (continuous output), which is about 5 MW.  Thus, two sets equaled 10 MW.

For the Saddle Mountains grade, there were two substations on either side of the hill: 

  • 6 MW substation at Doris on the 2.2% side
  • 4 MW substation at Kittitas on the 1.6% side

Added together, the substations equalled, 6 MW + 4 MW = 10 MW, which exactly matches the 10 MW power required by the double set of EF-5's.

If my analysis is valid, then it seems like the substations could handle two sets of EF-5's.

 

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Posted by Rails West on Saturday, January 1, 2011 1:09 AM

A bit about the Bipolars used on the Coast Division.  Per Holley's book, they were rebuilt in the 50's as follows:

  • Additional traction motor shunting for increased speed
  • Better traction motor ventilation for more horsepower
  • Roller bearings for high speed reliability
  • MU controls
  • Improved guiding truck centering for better tracking
  • High capacity flash boilers for reliable train heating
  • Streamlined carbody for looks

The E-5 was the first one rebuilt at Tacoma. 

(Aside:  The Bipolar that survives today is the E-2).

- Rails West

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Posted by erikem on Sunday, January 2, 2011 12:22 AM

Rails West

Out of curiosity, I looked up some power information on that locomotive combination.  Per Holley, one EF-5 was rated 6680 hp (continuous output), which is about 5 MW.  Thus, two sets equaled 10 MW.

For the Saddle Mountains grade, there were two substations on either side of the hill: 

  • 6 MW substation at Doris on the 2.2% side
  • 4 MW substation at Kittitas on the 1.6% side

Added together, the substations equalled, 6 MW + 4 MW = 10 MW, which exactly matches the 10 MW power required by the double set of EF-5's.

According to a 1956 paper by Laurence Wylie, the EF-5's were rated at 6680 hp continuous (the same as you wrote) and 8200 hp hourly. Current per motor is 230 amps continuous and 285 amps hourly. Current per EF-5 in parallel is 8 times that or 1840 amps continuous and 2280 amps hourly. Tractive efforts are 161,600 lbf continuous and 212,000 lbf hourly.

From a 1950 letter by Wylie on substation operation, each 2MW M-G set could produce 1,000 amps for two hours - after 1956, Doris had 3 - 2MW M-G sets and thus was capable of supplying 3,000 amps for two hours. I don't think there was enough feeder capacity for Taunton or Kittitas to provide the extra 1,560 amps. IIRC, there was a proposal to put a mercury arc rectifier substation (Beverly?) along with extra feeders to allow a pair of EF-5's to ascend the grade in full parallel and loaded to hourly ratings. At 14.5 mph, the EF-5's would have taken slightly over an hour to make the WB ascent.

FWIW, a pair of Joe's will pull in 3,000 amps at hourly ratings in full parallel.

- Erik

p.s. lbf = pounds force - even though pound is a unit of force, not mass, habits from exposure to fluid mechanics and dynamics classes die hard.

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Posted by CNW 6000 on Sunday, January 2, 2011 9:58 AM

Rails West

That was interesting about double sets of 4-unit boxcabs (class EF-5's) on one train.

Out of curiosity, I looked up some power information on that locomotive combination.  Per Holley, one EF-5 was rated 6680 hp (continuous output), which is about 5 MW.  Thus, two sets equaled 10 MW.

For the Saddle Mountains grade, there were two substations on either side of the hill: 

  • 6 MW substation at Doris on the 2.2% side
  • 4 MW substation at Kittitas on the 1.6% side

Added together, the substations equalled, 6 MW + 4 MW = 10 MW, which exactly matches the 10 MW power required by the double set of EF-5's.

If my analysis is valid, then it seems like the substations could handle two sets of EF-5's.

 

Forgive my intrusion to this topic as I have zero knowledge about electrified railroading (from the power supplied/usage aspect anyway) and will ask what's probably a stupid question:

In your post I've quoted, you state that the two substations power together could run two sets of two EF-5s or four engines.  How long/big was the area covered by these two substations in terms of miles from the point they provided power until they no longer provided power?  The thought I'm attempting to articulate is that four locomotives maximum working on trains seems like it would constrain the railroad from doing too much more business over that particular section of track.  As stated...I know nothing about the MILW or railroading from that era...so how does that limitation of 4 engines compare to a conventional (steam/diesel) subdivision in terms of how many trains could you get over the road-all other considerations being equal?

Thanks in advance.
Dan

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Posted by Rails West on Sunday, January 2, 2011 1:21 PM

Dan writes:

CNW 6000
How long/big was the area covered by these two substations in terms of miles from the point they provided power until they no longer provided power?

Thanks for asking.  I had exactly the same question!  That's why I didn't know if my comment was valid or not.

Erik mentioned in his post above that the reach of a substation had to do with the current carrying capacity of the line-side feeders.  Erik, can you help?

 

(Note: post edited for re-wording)

 

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Posted by erikem on Monday, January 3, 2011 12:35 AM

Dan, Rails West,

The question is far from stupid, the answer does involve a bit of very basic electrical engineering, math and details of the installation, specifically sizes of contact wire, feeders and rail.

The "as-built" description of the electrification can be found in CERA bulletin 116 on "page 34" (page number in quotes as that was from the original article and not for the book). The spacing between the Doris and Kittitas  substations was 23.0 miles, the spacing between the Taunton and Doris Substations was 34.9 miles. Contact wire for almost all of the Milwaukee electrification was a pair of 4/0 copper wires (211Mcm, where Mcm means 1,000 circular mils). Feeders on the system was typically a single 500Mcm copper cable, however the stretch between Doris and Kittitas was equipped with a pair of 700Mcm copper cables, and a pair of 500Mcm cables from Doris to the bottom of the grade, which 5.3 miles away. The line was equipped with 90 lb rail.

The limitations on how far a substation can provide power is defined by how much current can be consumed and how much voltage drop is tolerable. Voltage drop is simply current times resistance for DC wiring. A simple rule of thumb is that the resistance of 1 foot of 1 cmil wire (i.e. a round wire with a diameter of 0.001", which is 1 mil) is 10.6 ohms, thus 1000' feet of 1000Mcm cable will have a resistance of 0.0106 ohms. The resistance of rail is about the same as a copper conductor with an area of 10Mcm per pound per yard, a pair of 90 lb rails is equivalent to a 1,800Mcm copper cable.

For the stretch between Doris and Kittitas, the resistance of the overhead works out to 0.7 ohms, and the resistance of the return rails also work out to be 0.7 ohms, for a total resistance of 1.4 ohms. Assuming you're willing to tolerate a 1,000V drop, this would allow Kittitas to feed 1000/1.4=714 amps to a train at Doris (or vice versa), which is substantially less than the 2,000 amps that Doris could provide as built (3,000 amps after 1955). Halfway between Doris and Kittitas, the total resistance to each substation is 0.7 ohms, or equivalent parallel resistance of 0.35 ohms. With a 1000V allowable drop, the train could pull 1000/0.35=2850 amps, 2000 amps could be supplied with a 700V drop. More sharing could occur if the size of the feeder was increased, circa 1950 aluminum cable would get you one third the resistance for a given price than copper cable - going to 3,600Mcm copper equivalent for the positive feeder and 1,800Mcm copper equivalent for the negative feeder would double the amount of power that could be shared or double the distance between substations.

As for the "reach of a substation", the answer depends on the voltage regulation strategies used by the substations as well as substation spacing and feeder size. If the substations try for constant voltage in normal operation, then a train will be drawing power from both of the nearest substations, with more power drawn from the closer substation (and no power from more distant substations). If the substations use a drooping voltage to limit current draw, then the "reach" of the substation can exceed the substation spacing, however the distant stations will be providing minimal power.

As for more than one train taking power from a substation: The dispatcher and the engineers do need to take substations limits into account when dispatching or running trains. A busy line will typically have substations at closer intervals than a line with light traffic and those substations may have higher individual capacity. The designers of the San Diego trolley's Mission Valley line overlooked this issue - a major stop on the line is Qualcom stadium and they had problems with inadequate substation power in dealing with the end of game rush.

Hope this clears things up more than it confuses...

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Posted by CNW 6000 on Monday, January 3, 2011 8:36 AM

Thanks Erik.  I think I understand what you said.

My next question is if that 23 mile stretch of mountain (between Doris and Kittitas) could be used by a maximum of 4 electric locomotives (assuming that they're working to their full power & safe train handling procedures are followed) what would the comparable steam locomotive operation look like?  What about a diesel-electric?  Finally, what was the (at the time) cost for each: electric, steam, diesel-electric (crew, locomotive maintenance & fuel)?

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Posted by beaulieu on Monday, January 3, 2011 9:55 AM

CNW 6000

Thanks Erik.  I think I understand what you said.

My next question is if that 23 mile stretch of mountain (between Doris and Kittitas) could be used by a maximum of 4 electric locomotives (assuming that they're working to their full power & safe train handling procedures are followed) what would the comparable steam locomotive operation look like?  What about a diesel-electric?  Finally, what was the (at the time) cost for each: electric, steam, diesel-electric (crew, locomotive maintenance & fuel)?

Remember that you could have another train operating between those points as long as one was descending the grade, while the other was ascending. The descending train will be helping the substations power the ascending train.

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Posted by CNW 6000 on Monday, January 3, 2011 11:01 AM

...but that's kinda my point.  That setup could "only" allow two trains over that 23 mile stretch of track if I understand things correctly.  Following that theory the DS would have to 'hold' one train from ascending if another was already doing that?  I would think they'd have to else the substations/overhead would break down, right?  To me, two trains (4 units) is a low number but I don't know what the traffic demands were.

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Posted by nanaimo73 on Monday, January 3, 2011 12:12 PM

erikem
This is likely the reason that the Milwaukee kept the Joe's on the Rocky Mountain section.

- Erik

I read somewhere than the Joes were kept on the RM because the trackage was faster, and they would be more efficient. Grades were slight, outside of Piedmont - Butte, and Haugan - Avery, and there was a lot less curvature on the line.

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Posted by BEAUSABRE on Saturday, May 4, 2019 7:54 AM
According to June 2019 Trains, Page 39. "During the 1950's the only freight trains operating daily over the length of the transcontinental were Nos 263 and 264 and sometimes an extra" Allow for two Olympian Hiawathas and that's 4 maybe 5 or 6 trains a day. The passenger trains came off in 1961, so the 1963 addition of Nos 261 and 262 didn't change matters. Even if you throw in some locals, the odds were no more than one or two trains were out on the line at any given time. Electrical capacity would not appear to have bee a problem.
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Posted by CSSHEGEWISCH on Monday, May 6, 2019 7:40 AM

Electrical capacity may not have been a problem, but the lack of traffic on the line makes the electrification hard to justify in the first place.  It suggests that for traffic volumes, the Pacific Coast Extension was the nation's longest branch line.

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Posted by PNWRMNM on Monday, May 6, 2019 8:33 AM

While I agree that electrificaton of the MILW proved to be an error, as was building the Pacific Extension in the first place, its thin traffic was not an anomoly. The GN at Wenatchee WA in 1955 was regularly doing only one train a day each way west of Wenatchee according to the several train register pages at the PNRA Archives. Yes it was about 5200 tons, but still only one train. By the late 1960's was up to three per day each way plus seasonal grain extras on some days.

Today count is in the low 20s both ways combined, and limited by capacity of the Cascade Tunnel. All intermodal except ATK and one pair of carload trains.

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Posted by Overmod on Monday, May 6, 2019 9:00 AM

CSSHEGEWISCH
Electrical capacity may not have been a problem, but the lack of traffic on the line makes the electrification hard to justify in the first place.  It suggests that for traffic volumes, the Pacific Coast Extension was the nation's longest branch line.

It does have to be said that one premise of building the new transcontinental was that electrification would improve operating economy and performance.  This was in the waning years of the great 'interurban revolution' where electrification of part of standard-gauge service with self-powered cars was being tried -- as a perceived competitive advantage -- by several mainline railroads. Note the assumption that the world-class 3000V copper 'infrastructure' could be carried by crude poles and still be effective, an interurban-style 'economy'.

The end-to-end capacity of a railroad like the PCE would not have been limited by substation capacity, or necessarily by the trains per hour that could be handled by the particular substation restrictions. Think of it as a 'pipeline' with many trains operating in the non-electrified sections as well.  Against the lower peak deliverable amperage should be considered the increased working speed (and better equipment utilization) that the electrification would provide by contrast with contemporary steam working, combined with the lower out-of-service intervals required for running-equipment maintenance of electric vs. steam in the environment of either section.

We have already discussed the relative benefit of electrifying the 'gap' between the sections, with the consensus of the 'knowledgeable' being that the receiver should have authorized this as early as the 1920s.  It would be interesting to consider what might need to be changed in either existing substation to support 'through' traffic that might increase at particular times of day with continuous electrification, or conversely whether new 'yard' capacity at the endpoints could provide load-spreading to equalize 24-hour track capacity with limited substation output.

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Posted by Erik_Mag on Monday, May 6, 2019 2:00 PM

The substation capacity and feeder size puts limits on how much power a train can draw from the line, i.e. a heavy train will be forced to travel slower than a lighter train. Since the train would be drawing at most from two substations, track capacity would be limited by how quickly a train can traverse the distance between two substations. For the Coast division spacing of 28 mi and old GE motor speed of 16 MPH, figure two hours per train each way, so the electrification could support 12 trains each way per day. That number would drop by half if the majority of the trains required distributed power, the west bound beet trains typically ran at 7-8MPH as having two EF-5's required limiting the controller to full series.

The 1969 GE proposal included beefing up the line capacity of the electrification along with the use of C-C electric locomotives. These would have running speeds of approx 8, 16 and 24mph at max continuous tractive effort, with current draw per locomotive of 500, 1000 and 1500 amps. Running speeds for the old GE's were 8 and 16 MPH, while the Joe's were about 6, 12 and 24 MPH.

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Posted by PNWRMNM on Monday, May 6, 2019 5:43 PM

Eric,

I think daily capacity is half what you calculated, 12 trains total, not 12 each way.

Second, what beets? To the best of my knowledge the MILW never handled beets west of Otherllo. They did serve U&I at Scalley but any beets on MILW would have been local to their Moses Lake Branch. NP had a beet dump at Warden IIRC. NP got beets off the GN at Adrian for Scalley. NP also handled beets to Toppenish U&I from various points in the lower Yakima Valley.

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Posted by Erik_Mag on Monday, May 6, 2019 10:07 PM

Mac,

Heaviest draw for the electrical supply is on the grades, a train descending would be regenerating so be reducing the load on the substation... 12 trains per day is probably the realistic limit as 12 trains each would require some very careful dispatching.

"Beets" may be a memory error on my part or a mis-captioning. Pictured train in question was heading westbound towards Doris. An EF-5 running parallel would be drawing 1800 - 2000 amps in parallel and the Doris substation could do 2000 amps for two hours, hence the two EF-5's running in series. If the overhead had the capacity to support two EF-5's in parallel, the extra speed would have allowed using the 90 minute rating which would have been a 15% boost in tractive effort.

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Posted by Gramp on Wednesday, May 8, 2019 9:42 PM

Any idea what the top speed of the Olympian Hiawatha was under wire when it was pulled by the electrics?

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Posted by Overmod on Wednesday, May 8, 2019 9:49 PM

Gramp
Any idea what the top speed of the Olympian Hiawatha was under wire when it was pulled by the electrics?

I do know that when the bipolars were rebuilt in the Fifties they were rated for 70mph.  Whether that is service speed or maximum operating speed (net of the 10% cushion and all that) I don't know.

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Posted by Erik_Mag on Thursday, May 9, 2019 1:42 PM

The Westinghouse motors supposedly could reach 90MPH by using the shunt position intended for regenerative braking. The passenger Joes reportedly could hit a bit over 80MPH.

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Posted by CSSHEGEWISCH on Thursday, May 9, 2019 1:51 PM

I doubt that there were too many stretches in either division where either class could attain those speeds.

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Posted by Erik_Mag on Friday, May 10, 2019 12:24 AM

On the Coast Division, there were some long tangents betweem Hyak and Kittitas. On the Rocky Mountain section, there would be several spots between Missoula and Deer Lodge, along with some stretches between Piedmont and Eustis.

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Posted by CSSHEGEWISCH on Friday, May 10, 2019 7:23 AM

Concerning the proposed re-electrification mentioned in the June issue of TRAINS and elsewhere, I get the impression that it would have been 11,000 Volts AC with locomotives similar to E44's.  Does anybody know the particulars of this proposal and how much it would have cost?

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Posted by Erik_Mag on Friday, May 10, 2019 2:10 PM

The full proposal is on Michael Sol's website. Since the infrastructure was in place for 3000VDC, the plan was to upgrade the distribution network as well as filling in the gap. Most of the feeders on the Milw electrification were copper, the copper in the feeders would be scrapped, and the salvage value would be enough to provide aluminum feeders with even greater conductivity. The gap would be supplied by rectifier substations, and some of the existing substations would be replaced with rectifier substations with the M-G sets added to substations supplying steep grades (regeneration).

GE was proposing C-C locomotives that were eminently not copies of the E-44's. Motors would be GE 750 requiring 48-50" wheels, control would be standard contacts and resistors along with regenerative braking. The locomotives would have about the same TE and continuous power as the Joe's, and would arguably been better than the Joe's for the Milw. With the C-C arrangement, the motors could have been run all 6 in series, two sets of 3 in series and 3 sets of two in series. The St Paul pass trackage had several speed restrictions of 15 and 20 MPH, which would fit in well with the C-C's 8, 16, 24 mph running speeds versus the Joe's 6, 12, 24 mph running speeds.

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