In an ongoing effort to recognize the historic places that make Tucson special the Tucson Historic Preservation Foundation partnered with Old Pueblo Trolley to nominate to the National Register of Historic Places the restored Warren-Bisbee Bus #8.

As Bisbee grew dramatically at the turn of the 19th century, the demand for housing led the Calumet and Arizona Mining Company to establish the new town of Warren. To do this they formed The Warren Company. With the distance between old Bisbee and Warren being about 6 miles, the need for public transportation was indisputable. In March 1907 The Warren Company established the Warren-Bisbee Railway. Service began on March 12, 1908 using large interurban cars which were needed to carry the peak loads to the mines at shift change times.

Twenty years later, the streetcars, track and overhead electric line were in need of renewal. A decision was reached to convert to buses, and change the company name to Warren-Bisbee Bus Line. Service for the bulk of the day could be handled by four, 21-passenger, Studebaker buses. The heavy loads of miners going to and from work were hauled in two, 40-passenger Twin Coaches. On June 1, 1928, buses took over for the streetcars.

The Studebakers were replaced by two 24-passenger model 1204 Yellow Coaches in 1938. The Yellow Coaches served through World War II, along side the Twin Coaches which remained on the property. Both type buses were retired in 1951, having been replaced by Ford Transit Buses.

In 1951, the Warren-Bisbee Bus Line sold at least one Twin Coach and one Yellow Coach to the Southern Arizona Auto Company of Lowell. They were in turn sold to Orrin and Edna Soles of Warren who drove them to property they owned near the intersection of Double Adobe Road and Frontier Road about 10 miles east of Warren. They had a well drilled and power brought to the property and started to convert the buses to a rural retreat. Unfortunately, vandals began to damage the buses and they soon gave up the project, leaving the buses to further vandalism and decay from the weather.

In July of 1995 the Tucson based non-profit Old Pueblo Trolley contacted the Soles about donating both buses. The Yellow Coach, which was Warren-Bisbee Bus Line # 7, was moved to Tucson on August 19, followed by the Twin Coach on September 9.

On the return from a trip to Bisbee on July 1, 1995 to survey whether the two buses were worth saving, and what would need to be done to move them, Old Pueblo Trolley discovered the body of a second Warren-Bisbee Bus Line Yellow Coach (# 8) in St. David. Its body was in good shape compared to #7. However, # 7 still had many of the running parts and even some interior parts missing from # 8. Thus a decision was quickly reached to restore # 8 (if it could be obtained) using parts from # 7.

Inquiry at the nearest house led to the owners, Jack and Flora McRae, who agreed to donate the bus. The McRae family had purchased the bus it when it was retired, and converted it to a road side food concession stand. When that use ended, it was kept for storage. The axles had been removed to make a small trailer, which they no longer had a use for and donated along with the bus. On September 9, 1995, # 8 was moved to Tucson.

Despite years of neglect the body of bus # 8 was surprisingly intact. Most of the window glass and both doors remain extant which protected it from the weather. While the body of bus # 7 had been badly vandalized, it still has the motor, transmission and air compressor, along with both axles and drive train, as well as a number of interior parts, including steering wheel, instrument panel, remains of one seat, and most of the handrails making restoration of number 8 possible.

Model 1204 Twin Coaches are extremely rare. Out of the 770 of them built between 1938 and 1941 only one other is known to survive.

In July 2016 the Tucson Historic Preservation Foundation nominated the bus to the National Register of Historic Places with designation anticipated in early 2017.