With a powerful two-cycle engine in the form of a 6-cylinder V-type configuration, the SW1 was one of EMD’s first mass produced locomotives. When purchased in 1939 Western Pacific specified a welded frame, hence the SW designation. Produced along with the SC type switchers with a cast frame the 44’-5” length would be the switcher standard until 1966. Producing 600 horsepower, the small V-6 did not fill the full length of the frame leaving room for a large sand box in front of the radiator. The exhaust stacks of these early switchers where not on the centerline of the locomotive but offset to the left. Operating at 800 RPM each engine cylinder had a bore and stroke of 8½x10” and a displacement of 567 cubic inches.
With all gauges and controls on the left side of the cab shortly after delivery it was discovered that the fireman had relatively nothing to do except gaze out the window checking signals and switch alignment. One of the first modifications was therefore the branching of the pipe and installation of a bell ringer control on the right side of the cab for use by the fireman. Delivered with D7A traction motors and D4 main generators the 62:15 axle gearing was the standard for all freight equipment on the railroad. To assist with airflow through the radiator two cooling fans were placed behind the manually controlled shutters, which were behind the radiator. Speed of the fans was proportional to the speed of the engine. In 1954 EMD redesigned all of its switchers by incorporating the new 567C diesel engine and the V-6 600 horsepower SW600 replaced the SW1.
After finding Stockton to busy and the other yards to hilly the units settled down and spent most of their time in Sacramento and the Bay Area. In 1965, the diminutive units found themselves being transferred to the Sacramento Northern as numbers 401-403.
Paint differed from the SW1 with the addition of aluminum striping on the ends of the cab and hood as well as the battery box doors for better visibility. End footboards were also painted aluminum, as was the frame side. Aluminum and Orange paint replaced black by the end of 1950. These units were delivered without an exhaust stack, which the railroad added at a later date.
With the size and weight of freight cars getting larger, crews were beginning to have trouble completing switching requirements during their regular shifts. This coupled with the advancing age of the S1’s began to show in more maintenance downtime and ultimately dead storage. The 509 and 511 were the first to leave when traded to General Electric against the U30b order in December of 1967. At the same time the 504 was sold to the Sacramento Northern becoming their 405. Stockton, Terminal & Eastern traded two NW2’s for the 505 and 506 in 1968. Two years would elapse before the next S1 would leave the roster when the 507 was sold to Chrome Crankshaft who in turn sold it to the ST&E. 508 holds the honor of being the only S1 actually sold for scrap, that being in November 1971 going to Associated Metals in Sacramento. This left only the 510 on the roster. Thirty years old it became the only S1 to wear green paint and was sold to the ST&E in September 1972 thus bringing to a close this models presence on the WP.
Once on the property they were quickly dispatched to places like Oroville, which had an ascending grade at each end of the yard, which released the 511 for service at Stockton. Four went to Stockton and the other three to the Bay area. A final order for four units was placed on November 21, 1949. Arriving in February 1950 these units sported multiple unit connections and large number boards mounted on the end of the hood at a 45-degree angle. ALCo switchers until 1943 had narrow vertical shutter slats (551-552) on each side of the hood. In 1943 and 1944 horizontal slats (553-558) were used and after 1944 wide vertical slats (559-562) became standard.
A major difference between these units and the earlier S1, besides horsepower and weight, was a direct current generator with a General Electric exciter and a Buchi turbocharger. This switcher would become ALCo’s best selling unit ever. Powered by a turbocharged 6 cylinder 539 engine this would be the standard ALCO engine for all switchers until replaced by the 251 engine in the late 1950’s.
1968 found the first units leaving the roster as trade-in material to General Electric against an order for U30B’s. Tidewater Southern received two and Sacramento Northern one in 1969 and 70 respectively. Associated Metals in Sacramento received the 553 and 555 for scrapping in 1971 with the 556 and 558 being purchased by Chrome Crankshaft for possible re-sale. These two were eventually stripped for parts and scrapped. Purchase of the final three units 557, 560 and 561 by the Stockton Terminal & Eastern in 1976 removed the S-2 model from the roster.
Central California Traction Co. purchased the 563 in 1973 but returned the unit in 1976 when they acquired RS1 746 from the Tidewater Southern. It was then sold to the Stockton Terminal & Eastern who in turn sold it to Foster Farms in Livingston, California. Eventually it would be added to the collection of the Western Pacific Railroad Museum in Portola, California. The 564 was sold to the Stockton Terminal & Eastern.
Because of a long relationship with Westinghouse in the production of electric locomotives the VO1000’s were equipped with that companies traction motors which were larger than either GE’s or EMD’s. Built with a cast frame and type A trucks these units were found to be very good luggers in low speed service.
Identifying a need for more switchers Western Pacific approached both ALCo and EMD with less than desirable results. Baldwin it was found however had five slots available in its August and September production schedule. Although an order had been placed with EMD for NW2’s management decided to go with the Baldwins and cancelled the EMD order. Delivered late in 1945 with the then standard black and white switcher paint they received frame-mounted handrails and “Zephyr” paint in the 1950’s along with a cutout above the fuel filler on each side. Originally equipped with large cab side medallions these were replaced with smaller versions in conjunction with the new orange and silver paint. Solid orange replaced orange and silver paint in the 1960’s and some units received orange rotating roof beacons.
Although it had spent considerable time on the Sacramento Northern formal ownership transfer of the 584 did not occur until July 17, 1970 when it became the first unit to vacate the roster when sold to the Sacramento Northern as their number 407. It was later sold for scrap to Associated Metals in Sacramento, California on February 15, 1973. On August 27, 1970 the 582 was sold to Chrome Crankshaft and scrapped by Associated Metals at Benicia, California in October. 585 left the roster November 21 being sold to Chrome Crankshaft only to be scrapped in 1971. September 10, 1973 found the last two units being sold to the Purdy Company who in turn sold them to Joseph Simon & Son of Tacoma, Washington. They were in turn sold to the AutoTrain Corporation of Sanford, Florida. Unfortunately with the demise of AutoTrain these two units were scrapped leaving no examples of this model WP locomotive.
Modifications over the years included full-length handrails, spark arrestors, rotating roof beacons on the 602-604, and FRA mandated coupler cut lever modifications and footboard removal. Paint on most of the class migrated to solid orange in the early 1970’s followed by green in the mid seventies. All of the SW-9’s remained in service until the UP takeover late in 1982.
Finding itself short of power in the mid 1960’s the ST&E purchased these two locomotives when declared surplus by the UP in 1966. Once on the property they were found to be in need of major repair work and spent much of their time unavailable with borrowed WP ALCo S1’s filling the void. A year passed and finally in, October 1968, a deal was completed were the WP would trade ALCo S1’s 505-506 in exchange for the two NW2e units, ST&E 1000-1001.
Once on the property they were placed in the shops for rebuilding. So thoroughly were the 12-cylinder prime movers rebuilt the horsepower rating was raised from the original 1000 to 1200. Paint was the solid orange “Pumpkin II” with black zephyr lettering. While in the shop both units also received the Western Pacific standard five chime horn as well as full-length handrails. Both returned to service in 1969. Externally these switchers were very similar to previous EMC units with the exception of a smaller radiator with a toolbox on the front "porch" and large exhaust stacks not found on previous units.
Only one would remain on the WP roster proper until merger though as the 607 was transferred to the Sacramento Northern in May 1973. When transferred the unit received “Perlman Green” paint but retained its WP number. This was the last unit to be formally transferred to the SN from the WP. Both units returned to the UP roster in 1982 as a result of the merger. UP 1000 is preserved at Boulder City by the State of Nevada while the 1002 is at the Western Pacific Railroad Museum in Portola, CA as WP 608.
Finding the switcher fleet aging and car capacity increasing WP management placed an order with EMD for eight SW1500’s in early 1970. This order was subsequently canceled and substituted with an order for ten GP-40’s. Another attempt to acquire SW1500’s proved successful in 1972 when three units were ordered. Delivery came in May 1973. With the exception of headlights and high cab mounted number boards these units were very similar to rival Southern Pacific’s complete with flexicoil trucks, full-length handrails, multiple unit connections, and large 1100-gallon fuel tanks.
Numbered 1501-1503 to reflect their rating of 1500 horsepower the units came painted green with orange lettering and stripes on the pilots. Although originally delivered with a single chime horn, all three units eventually received the standard Nathan five chime horn. Originally assigned to Stockton they eventually were sent to Oakland/San Francisco. Generally two worked in Oakland and one worked San Francisco until ferry service was terminated. This was the last time Western Pacific would receive new switchers and these were not purchased by the railroad but instead leased.
Along with 10 units owned by MKT and Missouri Pacific these became, through merger, the first examples of this model switcher on the Union Pacific. All three WP units retained their numbers, when repainted at North Platte in 1984 and returned to Oakland for service. Renumbering into the 1300 series came in 1987-1988 with the 1501-1503 being numbered 1315-1317. All three were purchased by UP on January 3, 1989 when the original lease to WP expired. Reassignment came in 1990 when all three left California for service at Centennial Yard in Fort Worth, Texas. Another renumbering would come in 2001 when they became UPY1040-1942.