You guys are welcome to add on any more info.
434 SD40X 29025 7/64 Built with standard radiator; Sold to GM&O 950, now IC 6071
434A-434F SD40X 29873-29876, 30499, 30500 2-4/65 Built with flared radiators; Sold to UP 3040-3045
UP 3040 was traded to EMD in August 1986. UP 3041 was sold to Wilson Railway Co., Des Moines, Iowa, 17 March 1989, reconditioned and sold to PLM 3041 in August 1989, held at Wilson until mid 1990; rebuilt to SD40-2 by Morrison Knudsen, Mountaintop, Pa., completed as PLM 3041 on 30 September 1990; sold to Morrison Knudsen in April 1993, rebuilt to SD40M-2 by Morrison Knudsen, Boise, Idaho, completed as Morrison Knudsen (MKCX) 9051 on 15 November 1993; sold to Helm Financial, to Helm Leasing (HLCX) 6399; to Transportacion Ferroviaria Mexicana (TFM) 1507; leased to BNSF during 1998, still identified as TFM 1507. UP 3042 was leased to NdeM in November 1989 to October 1992; returned to UP and stored unserviceable; moved to Cheyenne, Wyo., during mid May 1993; stored at Cheyenne until sold to Dixie Engine & Equipment, Denver, Colo, in January 1999; sold to National Railway Equipment; moved to Mount Vernon, Ill., in March 1999.
UP 3043 was leased to NdeM in November 1989 to March 1990; stored unserviceable at Fort Worth, Tex.; sold to Phoenix Railway Corp., Spokane, Wash., in February 1992; sale rescinded; sold for scrap to Pielet Brothers Scrap Iron & Metal, McCook, Ill., 27 March 1992. 
UP 3044 was leased to NdeM in November 1989 to April 1990; stored unserviceable at Fort Worth, Tex.; sold for scrap to Southwest Railroad Car Parts, Longview, Tex., 13 July 1992.
UP 3045 was leased to NdeM in November 1989 to February 1991; stored unserviceable at Fort Worth, Tex.; sold to National Railway Equipment, 13 July 1992; sold to Morrison Knudsen, assigned MKCX 9406, not renumbered, retired on 11 August 1994; at Livingston Rebuild Center, Livingston, Mont., 6 September 1994.
434G & 434H SD40X 30501 & 30502 4/65 Standard radiators; Sold to UP 3046 & 3047, UP 3046 now W&LE 3046.
UP 3046 was sold to Wilson Railway Co., Des Moines, Iowa, 24 October 1988, in national lease service as WC-Oxford 3046; sold to Wheeling & Lake Erie Railway 3046 in August 1992; sold to a local bank and leased back to W&LE, rebuild completed in July 1998. UP 3047 was traded to EMD in August 1986.
EMD SD40 Demonstrators
After announcing its “40-Line” in June 1965, EMD completed nine combination test and demonstration units, using its then-new 645-cubic-inch-per-cylinder diesel engine and then-new AR10 alternator, mounted on the frame of the builder’s production SD35 locomotive.
The first unit, EMD 434, was painted first in EMD demonstrator colors, then in Santa Fe-like blue and yellow. It was later sold to Gulf, Mobile & Ohio and numbered 950 on that road. EMD completed eight others and numbered them 434A to 434H, painting them in an all-black scheme, from which stemmed their “Black Bird” nickname. Known as either SD40Xs or as SDX40s, depending on the source,
the units operated in test and demonstration service on several roads, including in Mexico and Canada, before EMD sold them to Union Pacific in February 1966 as UP 3040-3047. In mid-February 1966,
434C and 434D were sent to demonstrate in Canada (as CP 7001 and 7000, respectively), and then to Mexico in March.
Six units (434A-B and 434E-H) were delivered to UP immediately, arriving two months before the road’s first 40 regular-production SD40s, road numbers 3000-3039. The remaining two units (434C and 434D) were delivered to UP in April 1966 after their tours of Canada and Mexico. Later research has shown that EMD's own electrical schematics has these unique units labeled as SD40X.
The carbodies of units 3040-3045 (six units) had flared radiator sections, similar to those of production SD45s, but shorter. UP 3046 and 3047 had flat radiator sections, like those of production SD35s and SD40s, and were similar in appearance to SD35s, except for having three rooftop 48-inch radiator fans instead of two 48-inch fans bracketing a single 36-inch fan.
Because of their different electrical systems, UP usually kept these eight units together. In January 1974, UP assigned them briefly to potash trains at Soda Springs, Idaho. Within a month, the road reassigned them to the taconite unit ore trains between a mine in Wyoming and the U.S. Steel Corp. steel mill at Geneva, Utah, replacing eight unit sets of SD24s and SD24Bs which had been assigned to that particular service since 1971. In late 1975, UP equipped all eight units with Pacesetter speed control and transferred them to heavy switching and hump yard service in North Platte, Neb., and Kansas City, Kansas. Although they were equipped for slow speed heavy switching after 1975, the units were still not limited to yard duties. At times individual units would be assigned to road service as required, and continued to be seen at many locations until the mid 1980s. As examples: UP 3042 was seen in Seattle in March 1977, and 3040 was at Seattle in June 1979. After that time, and until their retirement, or lease to Mexico in 1989, they were used almost solely in heavy switching at North Platte.
http://utahrails.net/all-time/all-time- ... sd40x-3040
http://utahrails.net/up/diesels/up-dies ... #sd40-demo
