Challenger Renumbering
The Union Pacific Challengers were renumbered as they were converted from
burning coal to burning oil. They were also renumbered again when converted
back to burning coal. This renumbering made it difficult for those people who
tried to capture and record the various Challenger classes and corresponding
locomotive numbers.
Raymond Gutierrez
has studied the UP Challenger numbering system and has provided
the tables you see below. In 2020,
Steve Jackson provided updates to this information.
Group 1 -- Class CSA 1 (15 Locomotives)
| Serial | Year | Number | Year | Number | Year | Number | Year | Number | Year | Number | Notes |
|---|
| 68745 | 1936 | 3900 (coal) | 1943 | 3900 (oil) | 1944 | 3800 (oil) | | | | | Retired 08/1957 |
| 68746 | 1936 | 3901 (coal) | 1943 | 3901 (oil) | 1944 | 3801 (oil) | 1949 | 3701 (coal) | 1950 | 3801 (oil) | Retired 09/1957 |
| 68747 | 1936 | 3902 (coal) | 1943 | 3902 (oil) | 1944 | 3802 (oil) | 1949 | 3702 (coal) | 1950 | 3802 (oil) | Retired 12/1958 |
| 68748 | 1936 | 3903 (coal) | 1943 | 3903 (oil) | 1944 | 3803 (oil) | | | | | Retired 05/1959 |
| 68749 | 1936 | 3904 (coal) | 1943 | 3904 (oil) | 1944 | 3804 (oil) | 1949 | 3704 (coal) | 1950 | 3804 (oil) | Retired 07/1959 |
| 68750 | 1936 | 3905 (coal) | 1943 | 3905 (oil) | 1944 | 3805 (oil) | | | | | Retired 02/1956 |
| 68751 | 1936 | 3906 (coal) | 1943 | 3906 (oil) | 1944 | 3806 (oil) | | | | | Retired 07/1962 |
| 68752 | 1936 | 3907 (coal) | 1943 | 3907 (oil) | 1944 | 3807 (oil) | 1949 | 3707 (coal) | 1950 | 3807 (oil) | Retired 08/1957 |
| 68753 | 1936 | 3908 (coal) | 1943 | 3908 (oil) | 1944 | 3808 (oil) | | | | | Retired 04/1957 |
| 68754 | 1936 | 3909 (coal) | 1943 | 3909 (oil) | 1944 | 3809 (oil) | 1950 | 3709 (coal) | 1950 | 3809 (oil) | Retired 08/1957 |
| 68755 | 1936 | 3910 (coal) | 1943 | 3910 (oil) | 1944 | 3810 (oil) | 1949 | 3710 (coal) | 1950 | 3810 (oil) | Retired 09/1956 |
| 68756 | 1936 | 3911 (coal) | 1943 | 3911 (oil) | 1944 | 3811 (oil) | 1949 | 3711 (coal) | 1950 | 3811 (oil) | Retired 09/1956 |
| 68757 | 1936 | 3912 (coal) | 1943 | 3912 (oil) | 1944 | 3812 (oil) | | | | | Retired 12/1958 |
| 68758 | 1936 | 3913 (coal) | 1943 | 3913 (oil) | 1944 | 3813 (oil) | | | | | Retired 09/1956 |
| 68759 | 1936 | 3914 (coal) | 1943 | 3914 (oil) | 1944 | 3814 (oil) | 1949 | 3714 (coal) | 1950 | 3814 (oil) | Retired 06/1957 |
Group 2 -- Class CSA 2 (25 Locomotives)
| Serial | Year | Number | Year | Number | Year | Number | Year | Number | Year | Number | Year | Number | Notes |
|---|
| 68924 | 1937 | 3915 (coal) | | | 1942 | 3915 (oil) | 1944 | 3815 (oil) | | | | | Retired 12/1958 |
| 68925 | 1937 | 3916 (coal) | | | 1942 | 3916 (oil) | 1944 | 3816 (oil) | | | | | Retired 04/1957 |
| 68926 | 1937 | 3917 (coal) | | | 1942 | 3917 (oil) | 1944 | 3817 (oil) | 1949 | 3717 (coal) | 1950 | 3817 (oil) | Retired 06/1957 |
| 68927 | 1937 | 3918 (coal) | | | 1942 | 3918 (oil) | 1944 | 3818 (oil) | 1949 | 3718 (coal) | 1950 | 3818 (oil) | Retired 03/1961 |
| 68928 | 1937 | 3919 (coal) | | | 1942 | 3919 (oil) | 1944 | 3819 (oil) | | | | | Retired 07/1957 |
| 68929 | 1937 | 3920 (coal) | | | 1942 | 3920 (oil) | 1944 | 3820 (oil) | | | | | Retired 08/1957 |
| 68930 | 1937 | 3921 (coal) | | | 1942 | 3921 (oil) | 1944 | 3821 (oil) | | | | | Retired 04/1957 |
| 68931 | 1937 | 3922 (coal) | | | 1942 | 3922 (oil) | 1944 | 3822 (oil) | | | | | Retired 09/1957 |
| 68932 | 1937 | 3923 (coal) | | | 1942 | 3923 (oil) | 1944 | 3823 (oil) | | | | | Retired 07/1959 |
| 68933 | 1937 | 3924 (coal) | | | 1942 | 3924 (oil) | 1944 | 3824 (oil) | | | | | Retired 07/1957 |
| 68934 | 1937 | 3925 (coal) | | | 1942 | 3925 (oil) | 1944 | 3825 (oil) | | | | | Retired 04/1957 |
| 68935 | 1937 | 3926 (coal) | | | 1942 | 3926 (oil) | 1944 | 3826 (oil) | | | | | Retired 11/1956 |
| 68936 | 1937 | 3927 (coal) | | | 1942 | 3927 (oil) | 1944 | 3827 (oil) | | | | | Retired 12/1958 |
| 68937 | 1937 | 3928 (coal) | | | 1942 | 3928 (oil) | 1944 | 3828 (oil) | | | | | Retired 07/1959 |
| 68938 | 1937 | 3929 (coal) | | | 1942 | 3929 (oil) | 1944 | 3829 (oil) | | | | | Retired 07/1957 |
| 68939 | 1937 | 3930 (coal) | | | 1942 | 3930 (oil) | 1944 | 3830 (oil) | | | | | Retired 05/1959 |
| 68940 | 1937 | 3931 (coal) | | | 1942 | 3931 (oil) | 1944 | 3831 (oil) | | | | | Retired 06/1957 |
| 68941 | 1937 | 3932 (coal) | | | 1942 | 3932 (oil) | 1944 | 3832 (oil) | | | | | Retired 05/1959 |
| 68942 | 1937 | 3933 (coal) | | | 1942 | 3933 (oil) | 1944 | 3833 (oil) | | | | | Retired 11/1956 |
| 68943 | 1937 | 3934 (coal) | 1937 | 3934 (oil) | | | 1944 | 3834 (oil) | | | | | Passenger service; Retired 11/1954 |
| 68944 | 1937 | 3935 (coal) | 1937 | 3935 (oil) | | | 1944 | 3835 (oil) | | | | | Passenger service; Retired 11/1956 |
| 68945 | 1937 | 3936 (coal) | 1937 | 3936 (oil) | | | 1944 | 3836 (oil) | | | | | Passenger service; Retired 11/1956 |
| 68946 | 1937 | 3937 (coal) | 1937 | 3937 (oil) | | | 1944 | 3837 (oil) | | | | | Passenger service; Retired 07/1957 |
| 68947 | 1937 | 3938 (coal) | 1937 | 3938 (oil) | | | 1944 | 3838 (oil) | | | | | Passenger service; Retired 05/1959 |
| 68948 | 1937 | 3939 (coal) | 1937 | 3939 (oil) | | | 1944 | 3839 (oil) | | | | | Passenger service; Retired 08/1957 |
Group 3 -- Class 4664-3 (20 Locomotives)
| Serial | Year | Number | Year | Number | Notes |
|---|
| 69760 | 1942 | 3950 (coal) | | | Retired between 1958 and 1961 |
| 69761 | 1942 | 3951 (coal) | | | Retired between 1958 and 1961 |
| 69762 | 1942 | 3952 (coal) | | | Retired between 1958 and 1961 |
| 69763 | 1942 | 3953 (coal) | | | Retired between 1958 and 1961 |
| 69764 | 1942 | 3954 (coal) | | | Retired between 1958 and 1961 |
| 69765 | 1942 | 3955 (coal) | | | Retired between 1958 and 1961 |
| 69766 | 1942 | 3956 (coal) | | | Retired between 1958 and 1961 |
| 69767 | 1942 | 3957 (coal) | | | Retired between 1958 and 1961 |
| 69768 | 1942 | 3958 (coal) | | | Retired between 1958 and 1961 |
| 69769 | 1942 | 3959 (coal) | | | Retired between 1958 and 1961 |
| 69770 | 1942 | 3960 (coal) | | | Retired between 1958 and 1961 |
| 69771 | 1942 | 3961 (coal) | | | Retired between 1958 and 1961 |
| 69772 | 1942 | 3962 (coal) | | | Retired between 1958 and 1961 |
| 69773 | 1942 | 3963 (coal) | | | Retired between 1958 and 1961 |
| 69774 | 1942 | 3964 (coal) | | | Retired between 1958 and 1961 |
| 69775 | 1942 | 3965 (coal) | | | Retired between 1958 and 1961 |
| 69776 | 1942 | 3966 (coal) | | | Retired between 1958 and 1961 |
| 69777 | 1942 | 3967 (coal) | | | Wing wings in 1948; Retired between 1958 and 1961 |
| 69778 | 1942 | 3968 (coal) | 1946 | (oil) | Some sources say this locomotive was renumbered 3944 in 1946; converted back to coal; Retired between 1958 and 1961 |
| 69779 | 1942 | 3969 (coal) | | | Retired between 1958 and 1961 |
Group 4 -- Class 4664-4 (25 Locomotives)
Class 4664-4.a (10 Locomotives)
| Serial | Year | Number | Paint | Year | Number | Year | Number | Paint | Lettering | Wind Wings | Year | Number | Paint | Notes |
|---|
| 70158 | 1943 | 3975 (coal) | Black | 1945 | 3975 (oil) | 1946 | 3975 (oil) | Two-Tone Gray | Yellow | Yes | 1952 | 3708 (oil) | Black | Retired between 1958 and 1962 |
| 70159 | 1943 | 3976 (coal) | Black | 1945 | 3976 (oil) | 1946 | 3976 (oil) | Two-Tone Gray | Yellow | Yes | 1952 | 3709 (oil) | Black | Retired between 1958 and 1962 |
| 70160 | 1943 | 3977 (coal) | Black | 1945 | 3977 (oil) | 1946 | 3977 (oil) | Two-Tone Gray | Yellow | Yes | 1952 | 3710 (oil) | Black | Retired between 1958 and 1962; Displayed in North Platte, NE |
| 70161 | 1943 | 3978 (coal) | Black | 1945 | 3978 (oil) | 1946 | 3978 (oil) | Two-Tone Gray | Yellow | Yes | 1952 | 3711 (oil) | Black | Retired between 1958 and 1962 |
| 70162 | 1943 | 3979 (coal) | Black | 1945 | 3979 (oil) | 1946 | 3979 (oil) | Two-Tone Gray | Yellow | Yes | 1952 | 3712 (oil) | Black | Retired between 1958 and 1962 |
| 70169 | 1943 | 3980 (coal) | Black | 1945 | 3980 (oil) | 1946 | 3980 (oil) | Two-Tone Gray | Yellow | Yes | 1952 | 3713 (oil) | Black | Retired between 1958 and 1962 |
| 70170 | 1943 | 3981 (coal) | Black | 1945 | 3981 (oil) | 1946 | 3981 (oil) | Black | White | Yes | 1949 | 3714 (oil) | Black | Retired between 1958 and 1962 |
| 70171 | 1943 | 3982 (coal) | Black | 1945 | 3982 (oil) | 1946 | 3982 (oil) | Two-Tone Gray | Yellow | Yes | 1952 | 3715 (oil) | Black | Retired between 1958 and 1962 |
| 70172 | 1943 | 3983 (coal) | Black | 1945 | 3983 (oil) | 1946 | 3983 (oil) | Two-Tone Gray | Yellow | Yes | 1952 | 3716 (oil) | Black | Retired between 1958 and 1962 |
| 70173 | 1943 | 3984 (coal) | Black | 1945 | 3984 (oil) | 1946 | 3984 (oil) | Two-Tone Gray | Yellow | Yes | 1952 | 3717 (oil) | Black | Retired between 1958 and 1962 |
Class 4664-4.b (15 Locomotives)
| Serial | Year | Number | Paint | Notes |
|---|
| 70174 | 1943 | 3985 (coal) | Black | Restored to operation in April 1981. Converted to burn oil in 1990. Retired from UP's steam program in January 2020. |
| 70175 | 1943 | 3986 (coal) | Black | Retired between 1958 and 1962 |
| 70176 | 1943 | 3987 (coal) | Black | Retired between 1958 and 1962 |
| 70177 | 1943 | 3988 (coal) | Black | Retired between 1958 and 1962 |
| 70178 | 1943 | 3989 (coal) | Black | Retired between 1958 and 1962 |
| 70179 | 1943 | 3990 (coal) | Black | Retired between 1958 and 1962 |
| 70180 | 1943 | 3991 (coal) | Black | Retired between 1958 and 1962 |
| 70181 | 1943 | 3992 (coal) | Black | Retired between 1958 and 1962 |
| 70182 | 1943 | 3993 (coal) | Black | Retired between 1958 and 1962 |
| 70678 | 1943 | 3994 (coal) | Black | Retired between 1958 and 1962 |
| 70679 | 1943 | 3995 (coal) | Black | Retired between 1958 and 1962 |
| 70680 | 1943 | 3996 (coal) | Black | Retired between 1958 and 1962 |
| 70681 | 1943 | 3997 (coal) | Black | Retired between 1958 and 1962 |
| 70682 | 1943 | 3998 (coal) | Black | Retired between 1958 and 1962 |
| 70683 | 1943 | 3999 (coal) | Black | Retired between 1958 and 1962 |
Group 5 -- Class 4664-5 (20 Locomotives)
| Serial | Year | Number | Year | Number | Notes |
|---|
| 72792 | 1944 | 3930 (coal) | 1952 | 3700 (oil) | Retired between 1958 and 1961 |
| 72793 | 1944 | 3931 (coal) | 1952 | 3701 (oil) | Retired between 1958 and 1961 |
| 72794 | 1944 | 3932 (coal) | 1952 | 3702 (oil) | Retired between 1958 and 1961 |
| 72795 | 1944 | 3933 (coal) | | | Retired between 1958 and 1961 |
| 72796 | 1944 | 3934 (coal) | 1952 | 3703 (oil) | Retired between 1958 and 1961 |
| 72797 | 1944 | 3935 (coal) | | | Retired between 1958 and 1961 |
| 72798 | 1944 | 3936 (coal) | | | Retired between 1958 and 1961 |
| 72799 | 1944 | 3937 (coal) | 1952 | 3704 (oil) | Retired between 1958 and 1961 |
| 72800 | 1944 | 3938 (coal) | 1952 | 3705 (oil) | Retired between 1958 and 1961 |
| 72801 | 1944 | 3939 (coal) | | | Retired between 1958 and 1961 |
| 72802 | 1944 | 3940 (coal) | 1946 | (oil) | Converted back to coal after 1946; Retired between 1958 and 1961 |
| 72803 | 1944 | 3941 (coal) | | | Retired between 1958 and 1961 |
| 72804 | 1944 | 3942 (coal) | | | Retired between 1958 and 1961 |
| 72805 | 1944 | 3943 (coal) | 1952 | 3706 (oil) | Wing wings in 1948; Retired between 1958 and 1961 |
| 72806 | 1944 | 3944 (coal) | 1952 | 3707 (oil) | Converted to oil in 1946; renumbered in 1952; Retired between 1958 and 1961 |
| 72807 | 1944 | 3945 (coal) | | | Retired between 1958 and 1961 |
| 72808 | 1944 | 3946 (coal) | | | Retired between 1958 and 1961 |
| 72809 | 1944 | 3947 (coal) | | | Retired between 1958 and 1961 |
| 72810 | 1944 | 3948 (coal) | | | Retired between 1958 and 1961 |
| 72811 | 1944 | 3949 (coal) | | | Retired between 1958 and 1961 |
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