610 and its class were based on Lima's prototype "Super Power" 2-8-4 design, and the T&P rostered them to pull fast and heavy freight trains.

610 remains in storage under Texas State Railroad ownership, and it is towed outdoors for display during occasional events.

[7] Lancaster sought for the T&P to acquire faster and more powerful locomotives than their G-1 Class 2-10-2 "Santa Fe" types, to compete with intercity truck services and to assist the booming oil industry of Texas.

[5][8][9] The A-1 was tested on trackage owned by the T&P's future parent company, the Missouri Pacific (MoPac), and after observing the A-1's performance, T&P executives became impressed.

610-624) were classified as I-1As, since some of their design features were altered from those on the I-1s; their throttle type was changed to allow room for an ornate flange on the smokestack, and the boiler pressure was raised to 255 psi (1,758 kPa).

[3] At seventy locomotives, the T&P owned the largest fleet of 2-10-4s in the United States, until the introduction of the Pennsylvania Railroad's J1 Class in the early 1940s.

610 was mostly assigned in revenue service to pull heavy long-distance freight trains on T&P's 860-mile (1,380 km) mainline between Texarkana and El Paso, and en route, the locomotive traveled through the cities of Marshall, Longview, Dallas, Fort Worth, Abilene, Midland and Odessa.

610 was originally restricted to operate below 45 miles per hour (72 km/h), due to its poorly counterbalanced driving wheels, but in August 1938, No.

610 was rebuilt at the Lancaster shops in Fort Worth with Baldwin disc driving wheels and lightweight nickel-steel rods to eliminate its speed restriction, and it was reclassified as an I-1AR.

[18][1] Under Vollmer's guidance, the railroad began to order diesel locomotives from the Electro-Motive Division (EMD) to replace their steam fleet.

610 withheld from scrapping and donated to Amon G. Carter, who was a local publisher and a board chairman of the Southwestern Exposition and Fat Stock Show.

610 was put on static display at the show grounds, and a dedication ceremony was held where the locomotive was named after humorist and commentator Will Rogers.

[22][25] In April 1969, the Texas Christian University fraternity of Phi Delta Theta began to redevelop their property alongside the Will Rogers Coliseum, and in doing so, they were to rip up the spur line that connected No.

610 to operating condition to pull excursion trains between Fort Worth and Dallas, and created a nonprofit organization called the 610 Historical Foundation to begin the project.

[26][31][32] The foundation launched a fundraising campaign to cover the initial estimated restoration cost of $10,000, and they began searching for steam locomotive experts for help.

[17][26][32] In 1970, the 610 Foundation began to negotiate with the T&P for permission to pull passenger excursions on their Dallas-Fort Worth mainline, but MoPac’s vice president-operations, E. L. Manion, declined to allow the group trackage rights, citing it would disrupt the safety and regular freight operations on the right-of-way, and all suitable facilities were unavailable.

[16][28][35] Pearson hired Chicago-area railfan and steam locomotive mechanic Richard Jensen to lead the restoration process.

[61] The AFT Foundation had to decline, since they had already promised the city of Portland that they would return the locomotive to Oregon after the end of the Freedom Train tours.

[60][65] At Mineola, Texas, the locomotive experienced a hot box that subsequently had to be repaired while it stopped at Shreveport, and then go through flooded areas in Mississippi.

610 was moved inside the SOU's steam locomotive workshop in nearby Irondale to be overhauled and repainted, in preparation for its first excursion runs on the railway.

[22][60] The I-1AR received minor cosmetic decorations to symbolize its status on the SOU, including a brass eagle ornament above the front headlight, and a pair of round "SR" emblems on its air compressor shields.

[60][68] Trains magazine editor David P. Morgan subsequently requested to SOU president L. Stanley Crane that No.

610 pulled the Piedmont Limited/610 special excursion from Alexandria to Monroe, Virginia, it towed SOU research car No.

610 derailed in the Alexandria yard and damaged its pilot axle, and the rerailing process delayed its departure by 1 hour; at Monroe, No.

610 travelled to Roanoke to participate in the 1977 National Railway Historical Society (NRHS) Convention, but hot box issues delayed its arrival by seven hours.

610's performance; while it was able to pull long passenger trains across the railway’s system at 60 miles per hour (97 km/h), it continued to suffer mechanical problems on some occasions.

[38][81][82] Since nearby mainline railroads still refused to host steam excursions on their right-of-way, the 610 Foundation decided to search for a location to display No.

[23][38][82] In July, the 610 Foundation reached an agreement with the General Services Administration (GSA) to lease some undeveloped land adjacent to the records center for twenty years, and they quickly began construction on a building to store the locomotive.

610 maintained, and while Pearson still continued to explore ways to run it, he lost faith in using the locomotive for excursion service.

610 performed one test run on the TSR's right-of-way in October 1987, and the railroad put the locomotive up for lease for people willing to operate it, but no lessors showed interest.