Rio Grande F7's pulling California Zephyr

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The CB&Q, D&RGW and the WP all had passenger F units which did run on the CZ.  (The Q's only for a short time.)  Was there any consideration of power running through between the three railroads on the CZ?

Dominic Mazoch posted:

The CB&Q, D&RGW and the WP all had passenger F units which did run on the CZ.  (The Q's only for a short time.)  Was there any consideration of power running through between the three railroads on the CZ?

During the original discussions & planning for the CZ, the CB&Q people assumed that the various sets of motive power would indeed be "running through". That was the ONLY reason that the CB&Q purchased three sets of A-B-A F3 units, outfitted with passenger gearing and steam generators. Other wise the CB&Q would have purchase additional "E" units, as that was the motive power used on all their other passenger trains.

As soon as the CB&Q discovered that their A-B-A passenger F3 units were being cut-off the train in Denver, and subsequent "discussions" revealed that neither the D&RGW nor the WP had any intentions of operating THEIR portion of the CZ with SOMEBODY ELSES motive power, the CB&Q immediately ordered additional E7A, then E8A, then E9A units from EMD. Those three sets of "passenger" F3 units were reassigned to freight service, their gear ratios changed, and the steam generator equipment removed, all within the first year of CZ operation.

Some 4 striped F3's at Glenwood Springs.  Probably the best picture you will ever find.  Sorry it's not F7's.

http://www.railpictures.net/photo/423836/

Just a comment:

D&RGW 5481 looks like an F7A, but it is actually an FTA.  In 1950, it was badly wrecked in a derailment in Gore Canyon, sent to EMD for repair, and returned with an F7A carbody and a few upgrades, but was still an FT at its core.  I have always wondered if the cab still had the original No.8-EL brake valve with which the FT was originally delivered, or was that replaced with the then-contemporary 24-L brake valve at EMD.

The Locomotive Engineers' Journal published a couple of photos of the wrecked unit.  It was awful.

Good to know Tom. Howard, I have a handful of F3 pics, why are F7's so hard to find?

It does seem that 4-unit F3's and FT's were commonly seen on the California Zephyr.  The other D&RGW passenger trains normally did not require 6,000 horsepower, and most of the photos I've seen show 4500 horsepower or less, with Alcos and EMD's often used in multiple unit control.  Although I am sure I have seen photos of 4-unit F7's on the Zephyr, I believe they were in the bumblebee scheme.  You have raised an interesting question.

Here's one possibility: I have been unable to determine if there was a different gear ratio for passenger engines on D&RGW.  If not, then the FT's and F3's would have been ideal on the Zephyr, because they would have made F7's, with their higher continuous amperage ratings and automatic transition, available for freight service, where the additional electrical durability would have allowed more tonnage to be hauled.  The Zephyr did not need the four units for tractive effort; they were required for speed.  Manual transition* was not a major impediment in passenger service.  That's the only reason I can think of, and it is predicated on the unverified possibility that all D&RGW F-units had the same gear ratio.  If the gear ratios were different, then the FT and F3 units would have allowed the passenger F7's to be re-geared for freight and thereafter only used on passenger trains in unusual circumstances.

*  Unmodified FT and F3 units required that the Engineer reduce throttle and move the transition lever, and then notch the throttle up, at predetermined speeds when accelerating or decelerating.  This changed the traction motors to operate together in series, series-parallel, or parallel, respectively, to allow them to efficiently use the available current in different speed ranges.  Freight trains lost some speed each time the throttle had to be reduced to manually make transition.  One of the improvements built into F7's was automatic transition.  Most railroads did not retrofit their FT-F2 -F3 units with automatic transition.