Copy of text from Issue 4 of the Feather River Rail Society's publication "The Western Pacific Headlight". A Guide to WP GP40's By Larry Hanlon Early in June 1966 the Western Pacific took delivery of its first 10 EMD GP40s. These were a new model of locomotive for the railroad industry as well as for WP, and their acquisition resulted from WP's continuing program of purchasing replacement power to allow the retirement of worn-out FTs. The purchase of replacement power had begun in July 1960 with GP20's 2007-2010, but it got going in earnest in November 1963 with the purchase of the first GP35s. In service, the GP35s proved to be troublesome, and the WP looked to the new GP40 model for a reliable solution. After some initial difficulties, that is precisely what was achieved. Over a span of 14 years, WP ultimately ordered 6 groups of GP40s and GP40-2s, obtaining a total of 59 units. These locomotives became the mainstay of the priority merchandise and intermodal trains and could be found working anywhere on the system. There were physical variations in their external appearance, of course, and in this article we will look at the various types which exist. To my knowledge, a detailed definition of construction Phases for GP40s and GP40-2s has not yet been published, and we will not attempt to do so here. We will instead confine our attention to the appearance of WP's GP40s and GP40-2s. {GP40 Background} Late in 1965, the Electro-Motive Division of General Motors introduced a new line of locomotives based upon their newly-developed model 645 engine. At the top of the single-engined lineup, offering 3600 HP from a 20 cylinder version of the new engine, was the SD45. Next in line, offering 3000 HP from a more traditional V-16, were the GP40 and SD40. With these locomotives, EMD not only achieved parity with ALCo in the horsepower race, but also significantly raised the stakes. General Electric had started the horsepower race six years earlier with their introduction of the U25b, but nevertheless it took GE a year to match the 3000 HP output, and another year to reach 3300 HP. By that time ALCo had matched the SD45's output with 4 fewer cylinders, but that effort proved to be their last gasp in the locomotive business. EMD's new locomotives were generally very well received, and they had a huge success on their hands. The WP, NYC and other early purchasers of the GP40 experienced significant electrical problems with their units; in particular, the early high-power rectifier diodes were unreliable as they were still in their infancy, the traction motor field shunting was troublesome, the wheel- slip circuitry tended to become confused and leave a unit unloaded, and there were significant manufacturing quality problems with the traction motors which resulted in flashovers and damaged commutators. These problems were all eventually resolved and the GP40s went on to become a locomotive which was well liked by engine crews for its good riding qualities, responsiveness, and acceleration capabilites, as well as by management for its low maintenance demands. One legacy of the electrical problems with the GP35s and early GP40s, however, was the choice by many railroads to purchase SD40s instead of 4-axle power, thus contributing to the success of that model. On the WP, the high axle loadings permitted by the solidly built roadbed, the concern over higher track maintenance costs with 6-axle units, and the operating focus on high- value time-sensitive merchandise rather than slow, heavily-loaded coal trains caused WP to continue to concentrate on GPs. {The "Dash 2s"} As the Sixties came to a close, reliability, fuel efficiency, and low maintenance costs had become more important to the railroads than raw power. As a result, the horsepower race abated as most of the major carriers settled on 3000 HP units as the basis for their locomotive fleets. In response to these trends, in 1972 EMD advertised their new "Dash 2" line as having improved reliability at the same power levels. The primary changes in the Dash 2 models were in fact related to improving efficiency and reliability. The electrical control systems were modularized; that is, plug-in circuit cards, many of them transistorized, replaced hard- wired relays and thereby enabled easy and quick replacement of a failed component. New trucks, the 4-axle Blomberg M and the 6-axle HT-C, were designed to improve wheel-rail adhesion and thus obtain more tractive effort from a given basic locomotive design. And the central air system ducting was slightly changed to improve airflow efficiency. The SD40-2 was so well received that it, along with GE's C30-7, dominated locomotive purchases in the Seventies. After an initial burst, sales of the GP40-2 were disappointing as only about 300 were sold by the end of 1977. However, sales were strong in 1978-80, after which they again fell off until a late burst of 36 units in 1984. WP's units were among those built in 1979 and 1980. {Spotting Features} In the 6 years of GP40 production, the externally visible changes in appearance were surprisingly few. Over the twelve years of GP40-2 production several design changes occurred. At introduction, the original units differed only slightly in appearance from a GP40. The externally visible clues were the arrangement of battery box covers and under-cab access doors, the Dash 2 cab with its rear roof overhang and bolted cab side window panel, the inspection window in one of the doors on the long hood, the location of the central air system blower bulge and the addition of stiffening ribs, the shape of the dynamic brake blister, and the arrangement of hood doors in the radiator compartment. Many of the initial units were delivered on the new Blomberg M truck, but many customers including WP continued to order the earlier Blomberg B. By 1976 Phase II had appeared, characterized by the presence of the longer 88" nose, anticlimbers, and the corrugated air filters. Later small revisions included the mid-1979 adoption of welding instead of bolts to hold the cab side window panels in place, and the change to "Q" fans and exhaust silencers by late 1979. WP's orders for GP40-2s both fell into Phase II, and they show the characteristic variations of 1979 vs 1980 production. We'll now look at this more closely. {WP GP40 Types} There are 6 externally identifiable types of WP GP40s. These are summarized by road number in the accompanying table. The first 5 Types represent as- delivered condition, while Type 6 represents units exiting the M-K rebuild program. {Type 1} includes the 3501-3510, built in May 1966, and the 3511-3516, built in April 1967. These two orders are identical and are typical early-production GP40s. WP's options included the continued use front and rear of the large Pyle- National headlights which employ separate bulbs and reflectors. Since no pilot plows are attached, footboards are present. (By the mid-'70's, horizontally-oriented twin sealed beam headlights had replaced the Pyle- Nationals, and by the end of the decade the footboards had been removed). Roof fans are the flat-top style with the circular motor shield plate in the center of the grille. Paint and lettering is in the traditional orange and silver, with Scotchlite lettering on the hood and a WP medallion on the cab side. {Type 2} includes the 3517-3526, built in August 1970. These units were the first purchased in the Perlman/Flannery era, and were delivered in the new dark green paint. They were delivered with traditional EMD vertical twin sealed beam headlights between the number boards as well as signal lights on the low nose. A large pilot plow had been ordered, but a mixup at EMD resulted in the application of a small plow instead. Roof fans were of the flat-top, grille-only style without the motor shield plate. Internally, these units contained improved rectifier diodes as well as the IDAC wheel-slip circuitry which was a dramatic improvement over the earlier designs. Traction motor field shunting had also been eliminated, and the GP40 by now was a reliable design as delivered from the factory. {Type 3} includes the 3527-3544, built in August and September 1971. These units were delivered with nose lights, twin sealed beam headlights, a large pilot plow, and extended range dynamic brakes. The dynamic brake housings extend forward to the central air intake grilles on both sides of the locomotive. Other spotting features are the same as on the previous order. {Type 4} includes the 3545-3549, built in July 1979. These units were built well into the "Dash 2" era, and can be characterized as Phase IIa GP40-2s. They were delivered with Dynavane ("corrugated") radiator and central air intake screens, 88" noses and a heavy, full-width anticlimber across the front end. A large plow was applied but EMD somehow forgot the lights on the low nose. The arrangement of battery box covers, cab access doors, and hood doors matches other GP40-2s of that era. The units were equipped with cab roof mounted air conditioning, and the air horn was mounted on a pedestal to clear it. The firecracker-style radio antenna was mounted on a plate supported on posts above the dust blower bulge on the roof just behind the cab. Extended range dynamics were included; by now the blister on the right side had reverted to a short one while the left side blister continued to extend forward to the central air intake grille. Finally, these units were the first delivered in the "new image" orange and green paint scheme. {Type 5} includes the 3550-3559, built in April 1980. By this time EMD had adopted "Q" fans and the exhaust silencer roof hatch. All of the dynamic brake equipment is also relocated to the rear by about 10", and the blister on the right side is further shortened compared to the previous order. The left side blister still extends forward to the central air grille. This arrangement can be called Phase IIb. We are not sure why this change was made and are in the process of checking with EMD. The best guess at present is that more space was needed to clear the exhaust silencer housing inside the hood. This time the units were delivered with the nose lights and a large plow. The radio antenna, horn, and air conditioning were treated as on the previous order. These units also were delivered in the "new image" paint, and the 3559 was the last locomotive the WP purchased. {Type 6} includes the 3501-3516 after they emerged from the M-K rebuild program in the second half of 1980. They are characterized by vertical twin sealed beam headlights, signal lights on the low nose, and air conditioning, radio antenna, and horn mounting as on the Dash 2s. The pilot beam is cut out for FRA-style cut levers and the footboards are gone, but no plow has been mounted. Internally, the units were upgraded to Dash 2 standards. {Modelling the GP40s} In HO scale, modelling WP's GP40s and GP40-2s is a straightforward proposition. In an upcoming issue of The Headlight we will show you how. Meanwhile, this guide has hopefully provided the basic information to illustrate the external differences among the various orders of WP GP40s.