Katy Flyer of the Missouri, Kansas and Texas Railway
Hauled by locomotive 440, a 2-8-0 type built by Schenectady in 1901, more data on this webpage.
The last two of the MKT initials gave the name 'Katy'. According to this webpage, "In 1896, the Missouri Kansas & Texas Railroad announced the inauguration of the Katy Flyer, with service between St. Louis, Mo., and southwest Texas. By 1905, “The Fast Train to St. Louis” raced between Galveston, Texas, and St. Louis in about 37 hours.