The engine facilities at Sherman had to handle motive power that met two separate requirements. Between Sapulpa and Sherman, the bridges could handle anything on the Frisco up through the last series of the 4100-class, 4137-4164. South of Sherman, the Coopers rating dropped to E-56 to Irving, and to E-53.8 between North Ft Worth and West Yard (Ft Worth). South of Sherman, the 1306-class engines reigned.
