Union Pacific's EMD F-Units
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Last updated on August 25, 2015.
(This article is an edited and updated version of the original text used as part of an article by Don Strack, published in Diesel Era, Volume 2, Number 6, November/December 1991)
The Union Pacific Railroad was an early convert to the benefits of dieselization, and as such, was the owner of the largest fleet of EMD F3A cab units and F3B booster unit locomotives in the nation, with 89 cab units and 90 booster units. Southern Pacific had the second largest number with 80 cab units and 80 booster units. Southern Railway came in third with 79 cab units and 65 booster units. (The Southern Railway System, including Central of Georgia after 1960 and all of Southern's other subsidiaries, would later take the lead, operating a total of 187 F3As and F3Bs.)
While UP operated a large fleet of 1500-horsepower F3s, the road's F7 fleet consisted of only 20 F7As, 36 F7Bs, and two FP7s, compared with Santa Fe's large fleet of 215 F7 cab units and 247 F7 booster units. UP's 41 F9 cab units and 43 F9 booster units were not purchased new; instead they were rebuilt in 1958 and 1959 from F3A cab units and F3B booster units that were themselves built in 1947 and 1948.
While going over any list of owners of F-units, an interested reader will note nothing more than a general pattern in the dieselization of the nation's railroads. Many roads sampled EMD's FT locomotives, to investigate just how this new machine performed. Roads like the Santa Fe took the FT very seriously, buying 155 Cab units and 165 booster units. Other roads still held back when EMD offered the F3. Even the "Standard Railroad of the World", the Pennsylvania Railroad, bought only 90 cab units and 40 booster units. Between 1950 and 1955, the wave of dieselization swept the nation. The sales of EMD's F7s, with a production total of 2,362 cab units and 1,500 booster units, surprised a lot of people, except maybe EMD's own sales force. The AT&SF, B&O, NYC, SP and Wabash all bought over 100 F7As each, with SP and AT&SF buying more than 200 units each.
The builder of the F-units was the Electro-Motive Division of General Motors Corporation, better known simply as EMD. The "F" designation has been found to mean "Freight", with the "T" in FT standing for Twenty-seven hundred horsepower. The "F" designation used for EMD's freight units was retained throughout the production of the company's cab units, from the FT, to the F2, the F3, the F5, the F7, and finally, the F9, along with each of those models' different phases and variations. All of the F-units were equipped with increasingly improved versions of EMD's 567 V16 diesel engine, including the 567B, the 567BC, and the 567C. The electrical components, the generators, and the traction motors, were also regularly improved. These major improvements were the reasons that the model designations kept changing.
This article cannot hope to cover all of these changes in locomotive design, or even to try to explain them. There have been many books and magazine articles published on the subject of diesel locomotives. Particular examples come to mind; Kalmbach's two, The Second Diesel Spotter's Guide and The Contemporary Diesel Spotter's Guide are two of the best, along with the series about the "Diesel Locomotive, From D to L", in Trains magazine. Also the ground breaking efforts of Don Dover's Extra 2200 South must be mentioned whenever the subject of discussion is the diesel locomotive. Don, and the contributors to his magazine, have done more than any single source to raise the collective conscious of the rail enthusiast community about the intriguing differences between machines that all supposedly look alike.
This is the story of the EMD F-units of the Union Pacific Railroad. The original group of F-units for UP was ordered by the railroad on December 18, 1946. Union Pacific signed a purchase agreement with EMD for "fifteen new 1,500 horsepower passenger type Diesel-Electric Road Locomotives, consisting of five 'A' units and ten 'B' units; and seventy-two new 1,500 horsepower freight type Diesel-Electric Road Locomotives, consisting of forty-two 'A' units and thirty 'B' units."
As a side note, EMD turned ownership of the locomotives over to the equipment lessor, Bank of America, on May 12, 1947. UP finished paying for them and took full ownership nine years later on May 1, 1956.
The first EMD F-units delivered to the UP, built under EMD's order number E-818, were the 42 cab units and 30 booster units for freight service. The first units to arrive on the property came in May 1947 as two A-B-B-A sets. The first set was numbered 1400A, 1442B, 1443B, and 1401A and the second set carried numbers 1402A, 1444B, 1445B, and 1403A. Six months later, in October 1947, three more A-B-B-A sets were delivered, numbered 1404A-1409A and 1446B-1451B. The remaining units in the order were delivered in January and February 1948.
In February 1948, while the last of these freight units were being delivered, Union Pacific's Mechanical Department made a decision to change the numbering scheme for both its EMD and ALCO cab units. This new numbering plan would allow better control and easier reporting of the costs that were directly associated with these new locomotives.
The railroad expected to be using the cab units as 6000-horsepower four-unit locomotives. In line with this plan of operations the individual cab and booster units would be assigned matching unit numbers. In the original, as delivered numbering system, the group of booster units (UP 1442B-1471B) was numbered after the group of cab units (UP 1400A-1441A). In the new numbering plan the four-unit locomotive with number 1400 consisted of unit numbers: 1400 (the first A-unit, renumbered from 1400A); 1400B and 1400C, the two booster units, renumbered from 1442B and 1443B; and 1401, the other A-unit, renumbered from 1401A. As can be seen, the booster units were numbered with even numbers only.
As confusing as it might seem, the new numbering system does make some sense when considered with the thinking at the time. Both EMD and ALCO were selling their diesel locomotives as multiple unit replacements for steam locomotives, most of which averaged between 3,000 and 5,000 horsepower a piece. But the operating department soon discovered that the units of each "locomotive" could be intermixed as maintenance and power requirements changed.
During the 1950s this ability to intermix units was found to be the diesel locomotive's shining advantage over the steam locomotive; the locomotive, or rather locomotive units, on the front of each train could be added or subtracted to more efficiently match to the actual power needed to get the train over the road, with the associated savings in the cost of operation.
Union Pacific's decision to renumber the EMD and Alco cab units was made while the units in the F3s from original order were being delivered. The last 18 F3 cab units, originally assigned numbers 1424A-1441A, along with the last six F3 booster units in the order, originally assigned numbers 1466B-1471B, were either renumbered at the factory, or were built with the new numbers (UP 1424-1441 and 1424B,C, 1426B,C and 1428B,C). Some of the earlier units may have been received with the original numbers but were renumbered by the railroad at Omaha while being setup before going into service.
In September of 1947, the five A-B-B sets of passenger-equipped F3s from that initial December 1946 purchase agreement were delivered. These new passenger locomotives were numbered beginning with 964A, just after E7B number 963B that had been delivered the year before. The cab units, numbers 964A-968A, were equipped with water tanks for the steam generators on the booster units. The booster units, numbers 969B-978B, were equipped with both steam generators and water tanks. These passenger units were also renumbered in early 1948 into the new "B,C" numbering system, at the same time also being renumbered from the original 964A-class to the new 900-class, with numbers 900-904 and 900B,C-904B,C. As each "locomotive" consisted of only one A-unit (instead of two as with the freight units) along with two booster units, each A-unit number had a corresponding set of two booster units.
In May and June 1948 Union Pacific accepted delivery of 12 additional passenger-equipped F3s. The six cab units were numbered 905-910 and the six booster units were numbered 905B,C, 907B,C, and 909B,C. Again, as with the first order of passenger F3s, the cab units were equipped with water tanks and the booster units were equipped with steam generators in the rear of the units and water tanks in the front of each unit.
Additional passenger-equipped units came in late 1948 and January 1949. These 12 booster units, numbers 1430B,C to 1442B,C, were delivered with steam generators and water tanks.
Twenty-eight more F3s were among the 233 diesel locomotives purchased by Union Pacific in 1948 for passenger, freight, and switching service. These were the 28 units in the 1550 class, for use on the Northwestern District. The 14 cab units, numbered 1550 to 1563, and the 14 booster units, numbered 1550B,C to 1562B,C, were built between October 1948 and January 1949.
The first vacancies in the F3 roster came when F3A 1435 and F3B 1422C were wrecked at Coolige, Idaho on January 30, 1949. Both were wrecked beyond repair and were retired and scrapped. The retirement of these two units left Union Pacific with 65 Cab units and 57 booster units in the 1400 class. Had this accident happened a couple of years later these two units most likely would not have been scrapped. By 1951 EMD was getting into the wreck rebuild business, with the railroads sending in wrecked units and EMD returning them as like-new locomotives, or as modernized units rebuilt to the latest specifications.
By 1950 the railroad was looking toward the total dieselization of the Northwestern District, the district of operations on the Union Pacific made up of the former Oregon Short Line Railroad and the Oregon-Washington Railway and Navigation Company. These two railroads had been leased to Union Pacific on January 1, 1936, along with the Los Angeles and Salt Lake Railroad (which became the South-Central District). Union Pacific had controlled these companies since the early 1900s (LA&SL since 1921) and the lease would allow all of the roads to be operated as a single system.
Bad water on the South-Central District resulted in the district being completely dieselized by 1948 with the combination of the large fleets of F-units, Alco cab-units, and F-M road switchers. Rather than purchase more new locomotives for the Northwestern District, in 1950 the railroad chose to transfer some of the EMD F-units from the South Central District.
This transfer of F-units took place in 1950 and 1951 when 29 cab units and 31 booster units from the 1400-class were regeared and renumbered into the new 1500-class, joining the already existing 1550-class already assigned there. The reassigned locomotives carried road numbers 1500-1528 for the cab units and 1500B,C-1528B,C and 1530B for the booster units.
The F7s Arrive
In its continuing effort to compete for the locomotive dollars of America's railroads, EMD began producing the F7 in November 1948. The 1500-horsepower F7 differed from the 1500-horsepower F3 mainly by the installation of automatic transition, a 567BC diesel engine, and D47 traction motors.
Union Pacific's 20 F7As, 36 F7Bs, and two FP7s were delivered in 1951 and 1952, with one last unit coming in January 1953. The units that arrived during 1951 - in March, October, and November - came in two separate orders, with a total of 15 cab units and 30 booster units. These were UP's only orders for F7s. The four cab units, six booster units, and two FP7s that came in 1952, along with the one F7A that came in 1953, were not ordered as such, but came either as special purchases or as replacements for other, wrecked locomotives. UP's production F7s made up 15 A-B-B sets in the 1466 class. The units carried road numbers 1466-1480 and 1466B,C-1494B,C.
Union Pacific's first set of F7s was also UP's first wrecked F7s. On March 24, 1951, while on their very first trip west after being set up at Omaha, UP 1466, 1466B, and 1466C were wrecked at Green River, Wyoming. The three units were immediately returned to EMD for rebuilding, and were completed in June 1952 under EMD order numbers 8013, 8014, and 8015, using the EMD's special wreck repair/rebuild 8000 series order numbers.
In April 1952 Union Pacific accepted an A-B-B-A set of F7s that had been rebuilt from four wrecked F3s. F7 numbers 1464, 1464B, 1464C, and 1465 were rebuilt from F3s 1504, 1530B, 1558C, and 1553. The F3s had been wrecked at Orchard, Idaho on November 25, 1951 and were retired immediately. In this case, the actual units may not have rebuilt. Instead they may have served as unit for unit trade-ins.
Like the wrecked 1466, 1466B, and 1466C F7s mentioned earlier, these four units also were rebuilt under EMD's 8000 series wreck repair/rebuild order numbers. The 1464 was EMD order number 8008, 1464B was order number 8009, 1464C was order number 8010, and 1465 was done using number 8011. (The gap between order number 8011 for the 1465 and order number 8013 for the 1466 was filled by the rebuilding of Chicago and North Western E7A 5007B, wrecked on the UP at Wyuta, Utah in September 1951, later delivered to UP in March 1952 as UP E8A 925.)
The wreck of the four 1500-class F3s at Orchard, Idaho on November 25, 1951 involved a head-on collision between two trains that were to pass each other. The eastbound, Second 262, was waiting on the main track and the approaching westbound, Extra 1553 West, failed to stop and switch into the passing siding. The five men killed in the accident were in the cabs of the two trains' head-end units. Five of the six units on the two trains burned in the fire that started after the collision. Extra 1553 West, with one other unit and 68 cars, was traveling at 50 mph when it collided with Second 262, the eastbound with four units and 117 cars. A full ICC report of the collision is printed in the April 21, 1952 issue of Railway Age. The ICC explained the cause of the accident as the crew of the westbound being overcome by the exhaust gases of their locomotive.
Also in April 1952 two unique A-B sets of F-units were delivered to UP, just after the rebuilt F3s. In 1951 the Mexican government had ordered from EMD two FP7s and two F7Bs equipped for passenger service. Quoting the EMD April 17, 1952 letter of offering for the two 3,000 hp A-B locomotives:
"These locomotives were built for the Mexican Government Railway System who are not in a position to accept delivery for some time. We have, therefore, offered them for delivery in the month of April to American railroads."
Union Pacific accepted delivery of the units as numbers 911, 910B, 910C, and 912. One A-B set, UP 910 and 910B, was received at Omaha on April 28, 1952, and the other set, UP 911 and 910C, came two days later on the 30th. As delivered, the four units were geared to operate at 102 mph. As a side note, right up until the time that these four units were retired, they retained some of their Spanish-language labels and identification plates.
In October 1952 UP received a set of F7s that was built in late August 1952 specifically for demonstration service on the Chicago & North Western and on the all-steam Norfolk and Western. While on demonstration the four unit set carried EMD road numbers 459A, 459B, 459C, and 459D, which was the second cab unit.
Before the units were even built, EMD had planned to sell them as former demonstrators. On August 22, 1952 UP agreed to purchase them, at a reduced price, but still with "other extras standard to UP". As photographs in Trains magazine show (page 12, December 1952 and page 56, May 1953), the four units were fully painted and striped in UP's yellow, gray and red. But they were lettered for Electro-Motive and carried the GM shield logo on the nose door below the headlight.
When the demonstration on the N&W was completed, EMD reconditioned the units, put a new warranty on them and delivered the A-B-B-A set to UP in October 1952 numbered as UP 1481, 1496B, 1496C, and 1482. The metal builder's plates on the units themselves showed August 1952 build dates. Although the units were identified in all available documents as F7s, photographic research shows that they were equipped with the F3-style dynamic braking hatch. The base price on the two cab units was $161,000 and the base price for the two booster units was $147,500.
The railroad bought another former demonstrator unit, an F7A, in January 1953. EMD had built the unit as a demonstrator, road number 5040, in July 1950. As with the previous four units, the unit was completely refurbished, receiving a new-unit warranty, prior to its sale to Union Pacific as the 1483. UP 1483 was also equipped with the unique large snowplow seen on at least 10 of UP's F3 locomotives (and the later F9s), and was apparently the only F7 to be so equipped.
Conversions to F7s
Between 1952 and 1954 the 1400 class F3s that weren't reassigned in to the Northwest in 1950 were converted internally to F7s by the railroad's own shop forces. While other shops may have done some of the work, most of the conversion project was done at the new Salt Lake Shops. The conversion consisted of installing a 567BC engine in place of the original 567B engine, and updating the electrical components. Many of the F3s also received the F7-type of dynamic braking with the 36-inch diameter cooling fan. A retired railroad electrician from the Salt Lake shop has said that most of the upgrade program of the dynamic braking components was done in the railroad's Pocatello, Idaho shops during 1951.
Although the trade press announced that the F3 to F7 conversions were being done by EMD (one source said that there 54 units to be done on the UP), the upgrade was projected to be so extensive that UP and EMD decided to complete it at the railroad's facility in Salt Lake City. This project, along with the prospects of the same type of work to be done on both the AT&SF and the SP, was the reason that EMD opened its facility and warehouse in North Salt Lake City, Utah, about five miles north along the mainline to Ogden from the new Salt Lake Shops.
EMD's North Salt Lake facility was more than a warehouse. It was equipped as a rebuild center for both the 567 diesel engines and the rotating electrical gear (the generators and traction motors). Rather than Union Pacific sending the old equipment all the way from Salt Lake to La Grange, a suburb of Chicago, the railroad only had to move the equipment five miles north to EMD's new shop.
Ironically, after EMD vacated the facility in the late 1960s, in 1971 General Electric, EMD's competitor in the world locomotive market, moved into the shop and used it for the same purpose, calling it the Salt Lake Apparatus Service Shop. GE needed a facility for some limited rework on components of UP's U50Cs, along with work on other heavy rotating electrical gear for other divisions within GE. This GE shop was where some of the three-unit turbines were stripped after UP traded them in during the early 1970s. And as this is written (in 1991) the shop is still serving as a focal point for GE's service to its customers nationwide. An extensive truck modification has just been completed on UP's new 9100-class Dash 8-40Cs, and like the F3-to-F7 project with EMD, the workload was shared between the North Salt Lake facility and UP's Salt Lake Shops.
Unfortunately, research has yet to find any documents that show the extent to which the F3 to F7 conversion project was completed, including exactly which units were completed. Photographic resources are difficult to check because photographs of the 1400-class F3s are quite scarce.
Reassignment To Freight Service
With the arrival of Union Pacific's large fleet of E8s and E9s in 1953 through 1955, the railroad's passenger-equipped F3s were no longer needed in passenger service, even as secondary and back-up units. Between April and October 1953, 24 of the 27 units were regeared, renumbered to the 1451-class (from their low 900-class numbers), and reassigned to freight service. The remaining three cab units, 904, 905, and 909, were rebuilt to F7As by EMD at La Grange in late 1954 and early 1955, becoming the 1455, 1456, and 1460.
In February 1956 all four "Mexican" units (as the shop forces in Salt Lake called them), numbers 911, 910B, 910C, and 912, were also regeared and reassigned to freight service. At the same time they were also renumbered to 1498, 1498B, 1498C, and 1499. While in passenger service the units were almost used exclusively on Trains 35 and 36, the Butte Special, between Salt Lake City and Butte, Montana.
In late 1958, prior to the F9 rebuilding program, UP's F-unit fleet consisted of 111 cab units and 126 booster units (84 F3As, 88 F3Bs, 25 F7As, 38 F7Bs, and two FP7s, with many of the 1400-class F3s having been upgraded to F7s by this time). These totals may not make up a large number of units when compared to the F-unit fleets of some of the nation's other railroads. But when considered along with UP's other locomotives, like the ALCO FAs and FBs, the Gas Turbines from GE, and the large fleet of EMD GP9s, the F-units played a very important role in Union Pacific's dieselization program.
The F9 Program
By 1958 Union Pacific was again ready to modernize its diesel locomotive fleet. The turbocharging project for the GP9s begun in 1955 was found to be a success, and the railroad decided to pursue it to get better performance from the GP9s. By 1959 EMD had developed its own turbocharger, and UP ordered 30 SD24 cab units and 45 SD24B booster units, which were equipped with the new 2400-horsepower 567D3 engine with EMD's new turbocharger installed.
(The author completed an article about Union Pacific's GP9 turbocharging project in a 19-page article published by the Union Pacific Historical Society. The article was published in the July 1988, Volume 4, No. 3, issue of their quarterly magazine "The Streamliner." The text of the article, "Omaha GP20's, Union Pacific's GP9 turbocharging program," with updates.)
In 1958, in a continuing effort to upgrade their older locomotives, UP contracted with EMD to modernize the road's 1500- and 1550-class F3s. The rebuilt units were to be assigned to the Northwestern District as a new 500-class, formerly occupied by OSL's 2-8-0 Consolidations. The last 500-class 2-8-0s, numbers 533, 535, and 537, were retired in March 1958.
All of the 84 units in the 500-class F9s (41 F9As and 43 F9Bs) were completely remanufactured by EMD at La Grange, from the same number of F3s that remained in both the 1500 and the 1550 classes. This total excluded the four units that had already been retired and rebuilt in 1952 as F7s after the November 1951 wreck at Orchard, Idaho.
The rebuilding work included replacing the 567B or BC engine with a 567C engine. All new electrical gear was installed, including new D22 generators and new D47 traction motors. The units were considered by both the railroad and EMD to be F9 locomotives, albeit in remanufactured F3 carbodies. The only external indication of the F9 internal components was the 48-inch dynamic brake cooling fan on top and a rearrangement of the carbody panels to the F9 configuration of a louver set ahead of the first porthole. The class was assigned to the Northwestern District and the operating department tried to keep them from going either south of Ogden, Utah, or east of Green River, Wyoming.
The carbody appearance of the 500s varied considerably, being rebuilt from F3s scattered throughout the entire 1500 and 1550 classes. And since the units in the 1500 class varied from Phase II F3s to Phase IV F3s, so did the 500s. The carbody styles were mixed due to the fact that there was no consecutive or sequential order to either the 1400-to-1500 renumbering, or to the 1500-to-500 rebuilding. Because of this the only accurate method to determine the carbody style that any particular 500-class unit had is to have a photograph of that particular unit, and that unit may have changed over the years as the high fans were replaced by the low fans.
Union Pacific's fleet of EMD F-units served system-wide in both freight and passenger service, mostly on the South Central District, south of Ogden, and the Northwestern District, north of Ogden and west of Green River. Diesels were not common on the Eastern District, east of Ogden, until the use of steam was sharply curtailed in 1957. At that time the F-units also became common on that district as well.
Trade-in On New Units
The continuing modernization and upgrading of UP's diesel locomotive fleet brought new, more cost efficient units into use. As locomotives such as the three-unit Gas Turbines, the large fleet of GP9s, the thirty GP20s, and the seventy-five SD24s were purchased, the F-units began serving a less important, although still significant role in the operation of the railroad. The next step in modernization for the railroad was to bring in large numbers of EMD's GP30s, the first of the so-called "second generation" of modern locomotives.
The whole concept of fleet modernization was one that was being promoted by the locomotive builders; EMD for its GP30, and ALCO for its Century series. Some press releases even went so far as to say that the GP30s were being rebuilt from the railroads' older units. While some of the components (such as the trucks and traction motors) may have been similar, in reality the new locomotives were just that -- new. The locomotives that were supposedly being rebuilt were actually simple trade-ins, sometimes on a unit-for-unit basis. Some of UP's E8s and E9s are good examples of this, where certain older E2s, E3s, and E6s were "rebuilt" into newer E8s and E9s.
Union Pacific's first order of GP30s, 75 units in the 800-class, were built without trade-ins. However, the later 700-class GP30s, GP30Bs and GP35s, along with the DD35s, were built using F-units as trade-in material. The first trade-in F-units were sent to EMD during January 1963 and the 700-class GP30s began arriving in February. EMD records show that 76 F7s were traded for GP30s in 1963, and 22 F7s were traded for the GP35s in 1964. Also in 1964, 25 F7s were traded for the DD35s.
Most of the trade-in F-units were off the property by the time of the delivery of the last GP35 in July 1964, and the last DD35B in September 1964. The last GP30, number 734, came in June 1963, the last GP30B, number 739B, came in July 1963. However, there was one hold out -- the last 1400-class F-unit still on the railroad -- FP7 1499 was sent to EMD as trade-in on the SDP35s in mid 1965.
The first F9 was retired when UP F9A 516 was wrecked and was sent to EMD to be "rebuilt" as UP GP30 735 in February 1963. The retirements started in earnest in 1966 when 13 of the F9As, and 21 F9Bs were sent to EMD as trade-ins for SD40s. Seven of the remaining F9As, and nine F9Bs, were sent to EMD in 1968 on SD45s. F9B number 527B was sent to EMD in August 1970 on the DDA40X 6900s.
The remaining 19 cab units and 12 booster units were sold to the Rock Island in February 1972. Except for two of the units that were scrapped in December 1974, Rock Island kept the F9s in service until mid-1976 when they were traded to EMD on the Rock's order of GP38-2s.
With the sale of the F9s in 1972, the story of Union Pacific's fleet of EMD F-units comes to an end. These F3, F7, and F9 locomotives played a major role in the success of UP as one of the nation's most modern and progressive railroads.
One very apparent feature of units that were transferred to the OSL was the large snowplow that was applied to at least 12 units (11 F3s and one F7), plus another with a smaller pilot plow. Included in that list are:
(*) denotes photo confirmation
In addition to photos in private collections, the above list was gleaned from Dick Winegar's cab units book. A photo of UP 1438 taken in service on Sherman Hill in November 1949, and another of 1414 taken in July 1950 at Summit, California, may be the earliest photos of a snowplow equipped F3 units.
Unfortunately, photos of the 1400s that were renumbered to 1500s would be very rare because they were renumbered in 1950-1951, just two years after the units were delivered.
There is a UP photo of just the snowplow part on UP 1510 with what looks like a brand new plow, so maybe the addition of a plow was part of the regear-reballast-renumber for OSL service that created the 1500-series units. Another photo in the same group of UP 1510 was used on page 226 of Kratville's "Motive Power of the Union Pacific". That photo shows 1515 in the number board, but the other photo is definitely of 1510, with 1515 in the number board, same location, same unit, different angle.
Extended Side Door Handrails
Photo research reveals that for as-yet unknown reasons, Union Pacific extended the vertical handrails adjacent to the cab side doors, to reach up to and above the top line of the units' doors. Apparently, at the same time, a set of ladder grab irons was added to the side of the unit's nose, just ahead of the engineer's side window. No other information is available for this feature usually found only on units assigned to the Northwestern District.
On a UP F-unit, E-unit, etc. with two headlights, the lower one is the headlight. The upper one is a red (or red/white) warning light that was used when the train was stopped on the main line. The UP did not use the warning lights whle the train was in motion, as opposed to some RRs that used the rotating light as a warning to automobiles crossing the tracks. One specific use was that when a UP passenger train stopped in Grand Island, one direction involved the passengers crossing over the opposing mainline to reach the train. The signal light was used to "flag" opposing moves, warning of the dangers on the tracks. (Gary Binder, email to UP Modelers Yahoo discussion group, October 10, 2007)
"all about F's by Don Dover", Extra 2200 South, Volume 8, Number 3, Issue 20, January 1970, pp.19-21
"F-Unit Tally", by Dick Will and Dan Dover, Extra 2200 South, Volume 8, Number 4, Issue 21, February 1970, pp.24,25
"F-3", by Louis A. Marre, Railroad Model Craftsman, Volume 39, Number 3, August 1970, pp.19-25
"Union Pacific Railroad, An All-Time Roster", by Don Strack and Dan Dover, in five parts, Issues 67 through 71, particularly Part II in Issue 68 (for the 500 class F9s), Part III in Issue 69 (for the 900 class F3s), and Part V in Issue 71 (for the 1400 and 1500 class F3s and F7s).
"The Electro-Motive F3", by David Peck and Roger Boor, Mainline Modeler, Volume 3, Number 1, January/February 1982, pp.40-51
"The Electro-Motive F3", Part II, Mainline Modeler, March 1982, Volume 3, Number 2, March/April 1982, pp.40-51
Union Pacific Railroad Company, Diesel, Turbine and Electric Locomotive Historical Record, Office of Chief Mechanical Officer, Omaha, December 31, 1977
"UP F3's", by Dean Dickerhoof, The Streamliner, Volume 1, Number 1, January 1985, Union Pacific Historical Society, pp.18-24