meteor910
11-12-2009, 12:55 PM
SLSF 5000-5004,5006,5008-5017, EMD F3A
SLSF 5005,5007, EMD F9A (F3A rebuilds)
SLSF 5018-5039, EMD F7A
SLSF 5040-5051, FP7
Following are the early (1957) diagram sheets for the array of Frisco EMD F A-units. The original order was for 18 F3A & B sets. Note how the original diagram shows the locomotive as an A-B-B-A set. They were considering the locomotive to be a four-unit set at that time. Quickly, they realized that each unit was a locomotive, and a set of them could be arranged in any combination necessary to get the job done. This allowed much more flexibility for both operations and maintenance.
Note this first diagram also indicates an intent to order 24 F3 ABBA sets, not 18, in 1948. The corrections to the numbers on the diagram were made by me several years ago. Does anyone know the story behind the apparent change to 18 units from 24 F3 units?
In February, 1954, two F3A's, SLSF 5005 and 5007, were rebuilt into F9A's, 1750HP, including the addition of dynamic braking. These units were used on run-throughs with the ATSF (I think), who wanted d/b on the units to better handle the mountains on their routes west.
The F7's followed the F3's in 1949 and 1950. The FP7's, useful for both freight and passenger power, followed in 1950 and 1951. None of the EMD F A-units came from EMD with d/b's. Later, in 1954-1957, the Frisco would order F9B's with factory d/b's.
Ken
SLSF 5005,5007, EMD F9A (F3A rebuilds)
SLSF 5018-5039, EMD F7A
SLSF 5040-5051, FP7
Following are the early (1957) diagram sheets for the array of Frisco EMD F A-units. The original order was for 18 F3A & B sets. Note how the original diagram shows the locomotive as an A-B-B-A set. They were considering the locomotive to be a four-unit set at that time. Quickly, they realized that each unit was a locomotive, and a set of them could be arranged in any combination necessary to get the job done. This allowed much more flexibility for both operations and maintenance.
Note this first diagram also indicates an intent to order 24 F3 ABBA sets, not 18, in 1948. The corrections to the numbers on the diagram were made by me several years ago. Does anyone know the story behind the apparent change to 18 units from 24 F3 units?
In February, 1954, two F3A's, SLSF 5005 and 5007, were rebuilt into F9A's, 1750HP, including the addition of dynamic braking. These units were used on run-throughs with the ATSF (I think), who wanted d/b on the units to better handle the mountains on their routes west.
The F7's followed the F3's in 1949 and 1950. The FP7's, useful for both freight and passenger power, followed in 1950 and 1951. None of the EMD F A-units came from EMD with d/b's. Later, in 1954-1957, the Frisco would order F9B's with factory d/b's.
Ken