In 1906, the Texas & Pacific manufactured two examples of the Class E-1 in their own works in Marshall, Texas, which would remain their only Atlantic locomotives. The boiler was relatively small compared to the cylinder volume, but it operated at a relatively high pressure of 220 psi for the time. A special feature of the chassis was that the compensating levers also included the trailing axle in addition to the coupled axles, which is why this was also loaded with a high load of 58,000 pounds. This resulted in a tail-heaviness that led to unsatisfactory running characteristics. In addition, the tractive effort at this time was no longer quite sufficient for modern steel passenger cars.

For these reasons, the two locomotives underwent a complete conversion as early as 1917. To increase traction, the coupled wheels were reduced from 79 to 75 inches. Boiler pressure was reduced to 185 psi, but this was offset by increasing the cylinder diameter from 20 to 22 inches. The cylinders were now supplied by piston valves instead of slide valves. The boiler now contained a relatively large superheater and was oil-fired. The two locomotives survived in this form for a little over ten years until they were retired in December 1928 and January 1929.