This kit is a model of a 4-wheel car used by the Denver, South Park and Pacific (DSP&P) from the late 1870s well into the 20th Century. Precursors of the caboose, these were called "waycars" by the DSP&P. At least 18 of these cars were built for the DSP&P between 1878 or 1879 and 1884. The first were built by the DSP&P itself and the rest by the parent company, the Union Pacific (UP). The UP built an additional two for another subsidiary, the Central Colorado Railroad.