Union Pacific Cabooses
By Don Strack
Union Pacific Caboose Numbering
System 1915 Renumbering
Similar to the general 1885 renumbering of equipment for all of Union Pacific and its subsidiaries, in 1915 the railroad also completed a general renumbering effort. The cabooses of Union Pacific itself remained in their same 2000-2524 series. Oregon Short Line cabooses were renumbered from OSL 608-793 to OSL 3000-3143. The OWR&N cabooses were renumbered from OWR&N 200-330 to OWR&N 3500-3618.
LA&SL (still SPLA&SL at this time) was still semi-independent and retained its original 4200-series numbers for their caboose fleet as SPLA&SL 4212-4279. With full UP control of LA&SL in 1921, these cabooses were renumbered to LA&SL 3300-3363. The SPLA&SL 4200-series cabooses were originally SPLA&SL 200-series, so 4200-series may have been assigned during the 1915 renumbering, but as yet no documentation has come to light to support this.
Steel Caboose Renumbering to 25000 series
The plan for renumbering all cabooses into the 25000-series was adopted on December 30, 1958. The exact number of the first caboose renumbered to the 25000-series is not known, but 17 cabooses were renumbered during the month of January 1959. There were 395 steel cabooses to be renumbered, including 97 remaining CA-3s in the 3700-series, 99 remaining CA-4s in the 3800-series, and the 100 CA-5s in the 3900-series. All were renumbered to the 25000-series during 1959 and 1960, with the last eight cars being completed during June 1960. There were 99 CA-6s remaining in the 2700-series and these cabooses were renumbered to the 25000-series during 1959 through 1962, with the last steel caboose to be renumbered, UP 25306, being renumbered from UP 2706 in July 1962. Only those cabooses in the CA-3 to CA-6 classes were renumbered. The 100 cabooses in the new CA-7 class all received their 25000-series in 1959 as they were completed by the railroad's Omaha Shops.
The following table shows the steel cabooses involved in the 1959 renumbering:
| New Numbers | Class | Previous Numbers | Quantity | Notes |
| 25000-25099 | CA-3 | 3700-3799 | 97 | UP 3710, 3746, 3757 retired due to wrecks |
| 25100-25199 | CA-4 | 3800-3899 | 99 | UP 3849 retired due to wreck |
| 25200-25299 | CA-5 | 3900-3999 | 100 | |
| 25300-25399 | CA-6 | 2700-2799 | 99 | UP 2721 retired due to wreck |
Wooden Caboose Renumbering to 25000 series
In addition to the 395 remaining steel CA-3 through CA-6 cabooses, the remaining wooden cars were also part of the 1959 renumbering. The steel cabooses were completed quickly, between January 1959 and July 1962. Of the 256 wooden cabooses (199 CA-1, 39 CA , and 18 N.C.S.) still on the railroad's roster in January 1959, only 103 cars were actually renumbered to the new 25000-series numbers. For reasons not known today, the wooden caboose fleet was to wait until 1962 to be renumbered. The first wooden cabooses to be renumbered to the 25000-series were 30 cabooses renumbered in August 1962. The last wooden caboose to be renumbered was 3409, renumbered to 25844 in March 1965. Seventy-seven cabooses were renumbered in 1962; 26 in 1963; six in 1964 and five in 1965.
The plan to renumber all cabooses to the 25000 series came in December 1958. The steel cabooses were renumbered in January 1959 to July 1962, and the wooden cabooses were renumbered in August 1962 to March 1965. Although the reason for the delay in renumbering of the wooden cabooses is not currently known, one possible explanation may have been in anticipation of a ruling by the California Public Utilities Commission. Beginning in 1963, this ruling brought an end to the use of wooden cabooses by railroads in California. After 1963, although the wooden caboose fleet was slated for early retirement, UP would have needed a larger pool of cabooses to support the exclusive use of steel cabooses in California.
The number series from 25700 to 25899 were assigned to the remaining 256 wooden cars. Eighteen older Non-Common Standard cars on OWR&N (built between 1882 and 1891), and the 39 remaining CA-class cabooses on OWR&N, all built between 1905 and 1913, were assigned to the 25700-25739 number series, but of the 57 cars still in operation, and 40 potential numbers, only 27 cabooses were actually renumbered.
The grouping of the CA-1s from UP, and from the three subsidiary roads (OSL, LA&SL, OWR&N), together in the 25740 through 25899 number series (160 potential car numbers; 79 cabooses actually renumbered) indicates that not all of the 199 remaining CA-1 wooden cars were to be renumbered, perhaps due to whether of not they had been equipped with the better riding wood beam trucks.
Wooden Caboose 25000 Series Numbers:
| New Number | Class | Previous Number | Notes |
| 25700-25708 | N.C.S. | OWR&N 3500-3537 | 18 cars still in service, 9 potential numbers, 8 cars renumbered |
| 25709-25739 | CA | OWR&N 3545-3617 | 39 cars still in service, 31 potential numbers, 19 cars renumbered |
| 25740-25799 | CA-1 | UP 2525-2699 | 112 cars still in service, 160 potential numbers, 49 cars renumbered |
| 25800-25809 | CA-1 | OSL 3150-3192 | 18 cars still in service, 10 potential numbers, 7 cars renumbered |
| 25810-25839 | CA-1 | UP 3201-3274 | 40 cars still in service, 30 potential numbers, 16 cars renumbered |
| 25840-25849 | CA-1 | LA&SL 3373-3420 | 21 cars still in service; 10 potential numbers, 3 cars renumbered |
| 25850-25853 | CA-1 | OWR&N 3619-3631 | 8 cars still in service; four potential numbers, 4 cars renumbered |
Click here for a complete roster of wooden cabooses numbered in the 25000 series.
Transfer Caboose Renumbering to 25000 series
The 22 remaining transfer cabooses were also renumbered into the new 25000-series. There were 17 UP transfer cabooses still in service working their assignments in Omaha-Council Bluffs, Kansas City, and Denver, while the LA&SL cars were working in and around Los Angeles (some photos show LA&SL transfer cabooses in both the Omaha area and the Kansas City area, suggesting that they had been transferred). Although the 25000 renumbering plan was finalized in late December 1958, the UP transfer cabooses didn't receive their new numbers until August 1962 through September 1963, and the LA&SL cars weren't renumbered until October 1962 through March 1965.
Transfer Caboose 25000 Series Numbers:
| New Numbers | Previous Number | Quantity |
| 25900-25916 | UP 3283-3299 | 17 |
| 25917-25921 | LA&SL 3300-3304 | 5 |
