UP Steel Maintenance-of-Way Cabooses

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This page was last updated on September 27, 2019.

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Union Pacific's non-revenue, maintenance-of-way operations have always received rolling stock that was either obsolete or not cost effective to keep in regular revenue service. The caboose fleet was no different. Between 1904 and 1906, the railroad converted 75 Box Car cabooses from box cars built in the 1880s. In 1917, additional box car cabooses were converted, again from retired box cars built in the 1890s. These Box Car cabooses, both with and without cupolas, remained in active service from the time of their conversion through to the 1950s. They usually worked in maintenance-of-way service, but at times were also used in regular mainline, branch and local service, if there were insufficient numbers of regular cabooses available.

During the 1940s and early 1950s, the increase in traffic brought with it the need for more cabooses. While assigned to the same type of service as the Box Car cabooses, these "temporary cabooses" were numbered in the regular non-revenue series numbers, and were usually assigned to maintenance-of-way service. As with the Box Car cabooses, several temporary cabooses were also used in regular, mainline, branch and local service.

By the mid 1950s, the ranks of box car cabooses and temporary cabooses were slowly diminishing as the cars were damaged in wrecks, and as the cars themselves wore out and became uneconomical to keep repaired. The increasing numbers of steel cabooses allowed the older wooden N.C.S., CA and CA-1 cabooses to be used in non-revenue service and the wooden cars were regularly assigned these duties throughout the 1960s. With the last wooden cabooses being retired, UP began using the older steel cabooses in non-revenue service.

UP 903000 Series

In 1970 and 1971, three CA-3 steel cabooses were retired and permanently assigned to non-revenue service and renumbered into the 900000 maintenance-of-way number series as 903001, 903002, and 903003. In February to April 1975, another 13 CA-3 and CA-4 steel cabooses were retired and assigned to non-revenue service, specifically derrick train service. These 13 cars were numbered as 903217 to 903229.

Five more steel cabooses joined the non-revenue fleet in 1978 and 1979. All were originally in service as CA-4s and CA-5s. The numbers assigned were not consecutive, but as with all equipment in the non-revenue number series assigned as needed at the time of entering maintenance-of-way service among the retired box cars, flat cars, and other equipment used to keep the right of way in top notch shape.

Many of the cabooses assigned to Roadway service were painted in the standard Roadway paint scheme of the period, either Aluminum or Quartz Green, often known as Kenefick Green.

The need for non-revenue cabooses continued after 1984 when cabooses were no longer needed on mainline trains. In 1990, at least another six (possibly nine) cabooses were assigned to non-revenue service. Others may have also been assigned, but records are incomplete.

These non-revenue cabooses received the same utilitarian aluminum paint as all other non-revenue equipment. Beginning in 1971, all Roadway equipment, including cabooses, began to be painted a light green color, sometimes known as Kenefick green, after John Kenefick, president of UP from 1971 to 1986.

These cabooses saw service system-wide, and were assigned to welded rail trains, derrick trains, tie-renewal trains, ballast sled trains, and the annual steel gang trains that moved all over the railroad replacing rail and ties as needed. Two steel cupola cabooses have been painted solid yellow and assigned to the P-811 concrete tie train.

Following is a table of the known 903000-series cabooses assigned to non-revenue service:

Car Numbers Quantity Original Class Years Converted
UP 903001-903003 3 CA-3, CA-4 1970, 1971
UP 903005 1 CA-5 1984
UP 903011 1 CA-10 1993
UP 903014 1 CA-9 1994
UP 903015 1 CA-8  
UP 903018 1 CA-4 1978
UP 903038-903041 4 CA-4, CA-5 1979
UP 903217-903229 13 CA-3, CA-4 1975

(View a roster listing of the 903xxx series steel cabooses)

UP 906000 Series

The nine steel cabooses in the 906250 series road numbers were assigned in 1990 as office (or supervisor's) cars for Roadway service. (see The Mixed Train, December 1989, page 14)

The nine cabooses were numbered as UP 906250 to UP 906258, and were renumbered from cabooses in the CA-5, CA-7, CA-8 and CA-9 classes.

Several of the 906000-series cabooses were specifically assigned to welded rail train service and operated with the welded rail trains from the rail welding plants at Laramie, Wyoming, Dennison, Texas, and North Little Rock, Arkansas. The nine cars were converted by railroad personnel at each of the welded rail plants, but most of the nine cars set aside for the Roadway office car program in 1990 were not completed, and many have either been retired or remain stored and only partially finished at several Roadway shop locations. Several of the nine cars in the 906250-series were simply assigned to work train service and to local service without receiving any special conversion.

MP 7500 Series

Former Missouri Pacific cabooses in UP MOW service.

Beginning in December 1994, several former Missouri Pacific compact body cabooses were rebuilt to serve as Maintenace of Way office cars. Numbered as MP 7500-7514, most of the the cars had their interiors rebuilt to include bench seating along the interior walls, and were painted in UP's standard Roadway green.

The conversion work was done by Parsons Railway Shops, the privatized former MKT shops in Parsons, Kansas, and was still under way by October 1995, with nine cars having been completed. Upon completion, the cars were assigned to Roadway trains.

Reports indicate that nine of the 15 cars were actually completed by the time the program ended in about 1996, at about the same time as the UP merger with SP, and possibly because of it.

Three cars were seen in December 1999 at Pine Bluff, Arkansas, in work train service: MP 7504 (ex MP 13823); MP 7513 (ex MP 13913); and MP 7514 (ex MP 13074). Also in December 1999, MP 7505 was seen in work train service at Overton, Texas.

As late as May 2001, many of the cars were in local service in Tulsa, Oklahoma, and Fort Smith, Arkansas. MP 7508 and 7509 were stored at Cheyenne, Wyoming, still in their original MP red paint scheme until 7508 was assigned as a tool car for the Ohio crane working in Iowa. MP 7509 remains stored at Cheyenne, Wyoming.

MP 7512 was seen at Echo, Utah, on September 20, 2013, and again at Pendleton, Oregon on September 21, 2019.

MP 7500     1
MP 7501     2
MP 7502     3
MP 7503     4
MP 7504 MP 13823   5
MP 7505     6
MP 7506     7
MP 7507     8
MP 7508 MP 13752   9
MP 7509     10
MP 7510     11
MP 7511     12
MP 7512     13
MP 7513 MP 13913   14
MP 7514 MP 13074   15


  1. MP 7500;
  2. MP 7501;
  3. MP 7502; held at Butler, Wisconsin as of August 1, 2019
  4. MP 7503;
  5. MP 7504;
  6. MP 7505; held at St. Louis as of September 24, 2019
  7. MP 7506; held at Pryor, Oklahoma as of March 24, 2019
  8. MP 7507;
  9. MP 7508; stored during 2005 at Cheyenne, Wyoming (still in MP red paint); held at Oskaloosa, Iowa, as of July 5, 2019
  10. MP 7509; stored during 2005 at Cheyenne, Wyoming (still in MP red paint); wrecked before September 2007; both ends badly damaged
  11. MP 7510; held at Laramie, Wyoming, as of August 28, 2019; out of service, awaiting scrapping "dismantle on site 8/28/2019 cannot move"
  12. MP 7511; held at Laramie, Wyoming, as of February 15, 2019
  13. MP 7512; held at Pendleton, Oregon, as of September 21, 2019
  14. MP 7513; held at Laramie, Wyoming, as of February 15, 2019
  15. MP 7514; (no record, as of September 2019)

Roster Listing 900000 Series

Class Date
UP 903001 CA-3 May 1942 UP 25024 Dec 1971    
UP 903002 CA-3 May 1942 UP 25025 Aug 1971    
UP 903003 CA-4 Sep 1944 UP 25173 Jun 1970   1
UP 903005 CA-5 Aug 1952 UP 25283 Jul 1984   2
UP 903011 CA-10 -- -- --   3
UP 903014 CA-9 Jun 1967 UP 25673 Sep 1994   4
UP 903015 CA-8 Nov 1964 UP 25589 29 Sep 1994   5
UP 903018 CA-4 Oct 1944 UP 25107 Dec 1978   6
UP 903038 CA-4 Oct 1944 UP 25180 Sep 1979 Dec 1981  
UP 903039 CA-5 Jul 1952 UP 25210 Jan 1979    
UP 903040 CA-5 Jul 1952 UP 25215 Apr 1979    
UP 903041 CA-5 Aug 1952 UP 25225 Mar 1979    
UP 903217 CA-3 May 1942 UP 25022 Feb 1975   7
UP 903218 CA-3 Jul 1942 UP 25098 Apr 1975    
UP 903219 CA-3 Jun 1942 UP 25056 Feb 1975   8
UP 903220 CA-3 Jun 1942 UP 25059 Feb 1975 Sep 1985 9
UP 903221 CA-4 Sep 1944 UP 25126 Mar 1975 Apr 1984 10
UP 903222 CA-3 May 1942 UP 25023 Mar 1975 Oct 1976 11
UP 903223 CA-3 Jun 1942 UP 25050 Mar 1975 Apr 1984 12
UP 903224 CA-4 Oct 1944 UP 25108 Mar 1975   13
UP 903225 CA-4 Oct 1944 UP 25150 Apr 1975   14
UP 903226 CA-3 Jun 1942 UP 25053 Apr 1975 Aug 1983  
UP 903227 CA-4 Sep 1944 UP 25100 Apr 1975   15
UP 903228 CA-4 Nov 1944 UP 25157 Apr 1975 Jul 1985  
UP 903229 CA-4 Oct 1949 UP 25186 Apr 1975    
UP 906250 CA-5 Aug 1952 UP 25281 Apr 1990 2004 16
UP 906251 CA-9 May 1967 UP 25634 Apr 1990   17
UP 906252            
UP 906253 CA-7 Mar 1959       18
UP 906254 CA-7 Mar 1959 UP 25463 Oct 1990   19
UP 906255 CA-8 Nov 1964 UP 25578 Apr 1990 May 1990 20
UP 906256 CA-9 May 1967 UP 25641 Oct 1990   21
UP 906257 CA-8 Oct 1964 UP 25548 Oct 1990   22


  1. UP 903003 was last assigned to system welded rail train; usually stored at Laramie, Wyoming; retired and sold; moved to Boulder, Colorado; as of October 2013, offered for sale after area surrounding the caboose was damaged by extensive floods in the Boulder area.
  2. UP 903005 was briefly painted and lettered as WPMW 25283 during early July 1984; donated to Feather River Rail Society, Portola, California in 1985; repainted in August 2003 back to UP yellow and renumbered back to UP 25283. (2003 update from David Epling, email to Union Pacific discussion group, message no. 6042, dated August 25, 2003)
  3. UP 903011 was converted to Roadway service in 1993.
  4. UP 903014 was converted to Roadway service in 1994. Former number confirmed by inspection of car while in storage at Cheyenne, April 2003. Stored at Laramie, Wyoming; moved to Cheyenne; sold in 2004 to the Kankakee Railroad Museum in Kankakee, Illinois, located at the old Illinois Central Depot. (2004 update from Tom Taylor, by way of Jim Harrawood and Roger Kirkpatrick, September 19, 2004)
  5. UP 903015 was last assigned to Laramie, Wyoming, welded rail train; renumbered to UP 903015 in September 1994; seen in Cheyenne in late 1990s; retained its original yellow body color, but received a green paint patches under its new 903015 road number; sold to Rio Grande Pacific and shipped to New Orleans & Lower Coast Railroad (officially retired by UP on September 30, 2001; already on NO&LC property). Not used by NO&LC, stored at Belle Chase, Louisiana. In late March 2004, UP 903015 was moved by UP from its location at Goldsboro, Louisiana to Westwego, Louisiana, where it was picked up by UP for movement to Idaho Northern Railroad at Payette, Idaho. The car was in Council Bluffs, Iowa, on April 11, 2004. (Belle Chase Information from Greg Slaton, via April 28, 2011 email from Roger Kirkpatrick) (2004 information from Joel Boucher, via Thorton Waite)
  6. UP 903018 was last assigned to system welded rail train, circa 1985; usually stored at Laramie, Wyoming.
  7. UP 903217 was sold to Alter Trading Co., Council Bluffs, Iowa, April, 4, 1990, scrapped.
  8. UP 903219 was last assigned to Portola wreck train, circa November 1983; displayed as UP 25056 in city park at Green River, Wyoming
  9. UP 903220 was donated to Old West Frontier Days Museum, Cheyenne, Wyoming, February 1986; displayed as UP 22605; sold to a private individual and moved in July 1991.
  10. UP 903221 was donated to Centennial Valley Historical Association, Centennial, Wyoming, May 1985, delivered in July 1985.
  11. UP 903222 was wrecked on 24 July 1976 at Rock Springs, Wyoming.
  12. UP 903223 was seen at UP's yard in Yermo, California in January 1985. (Information from Randy Keller, via Roger Kirkpatrick)
  13. UP 903224 was last assigned to Salt Lake City derrick train. Painted in, August 1983 with aluminum body color and black-edged red lettering.
  14. UP 903225 was last assigned to Las Vegas derrick train. Donated after September 1984 to Barstow Unified School District, Yermo, California; sold to a private individual and possibly used as a concession stand at a ball park in the Barstow area.
  15. UP 903227 was last assigned to Pocatello derrick train, October, 1984; used on Pioneer Local north from Salt Lake City in 1988-1991.
  16. UP 906250 was seen in transit westbound in Utah in 2001; the last location for UP 906250 in UP's TCS car tracking computer system was Roseville, California in December 2001, showing that it was renumbered from UP 25281; stored at Oroville, California until it was sold in summer 2004 to the Allred family and moved to their property in Tehama County, California, about 30 miles west of Corning, California. (A different caboose is displayed as UP 25281 at Walters, Oklahoma, displayed there since May 1990)
  17. UP 906251 was last shown in railroad records was at Rawlins, Wyoming; by July 2010 the car was in storage as part of the Heritage Collection at Cheyenne, Wyoming.
  18. UP 906253 retained its original yellow body color, but received a green paint patches under its new 906000-series road number; sold to a private individual in Fort Collins, Colorado
  19. UP 906254 was last assigned as the office car for the Fairmont Tamper concrete tie train during August 1998, located at Tucson, Arizona; repainted yellow by October 2006; by July 2010 the car was in storage as part of the Heritage Collection at Cheyenne, Wyoming.
  20. UP 906255 is displayed at the Nevada State Railroad Museum in Boulder City, Nevada
  21. UP 906256 was donated to Nevada State Railroad Museum, Boulder City, Nevada
  22. UP 906257 retained its original yellow body color, but received a, green paint patches under its new 906000-series road number.