The Texas & Pacific Railroad received the very first purposely designed 2-10-4
built in North America. The Lima Locomotive Works delivered it in 1925 as part
of an order for ten "Texas" type locomotives. This group was designated as
Class I-1 and was assigned road numbers 600-609. They had 63.5" diameter
drivers, 29" x 30" cylinders, a 250 psi boiler pressure, a tractive effort of
83,000 pounds and each weighed 448,000 pounds.
As was the custom, the first railroad to receive a new wheel arrangement was
given the honor of giving of naming it and T&P selected the name "Texas" for the
Fifteen more "Texas" type locomotives were delivered from Lima in 1927. These
Class I-1a 2-10-4s were given road numbers 610 through 624 and were duplicates
of the first ten, except the boiler pressure was raised to 255 psi, which
increased the tractive effort to 84,600 pounds.
In 1928, thirty more were delivered fifteen were designated as Class I-1b and
assigned road numbers 625 through 639 and fifteen were designated as Class I-1c
and assigned road numbers 640 through 654. All thirty were built by Lima and
were very similar to the 1927 group except the weight of each was 452,000
A final 15 designated as Class I-1d with road numbers 655 through 669 arrived in
1929 to complete T&P's roster of seventy. These last locomotives, built by
Lima, were very close copies of the previous class except each weighed 457,000
There is one surviving T&P "Texas", number 610 which is owned by the Texas Stare
Railroad and is on Static display in Palestine, TX. Number 610 was restored to
operating condition and it hauled the American Freedom Train throughout the
southwest during the 1976 bicentennial celebration.
Class I-1 (Locobase 99)
Data from table in 1930 Locomotive Cyclopedia, supplemented by data from T&P 1 - 1950ca Locomotive Diagrams supplied in May 2005 by Allen Stanley from his extensive collection.
This was the class that named the 2-10-4 wheel arrangement and certainly the T & P was one of the largest single users of these enormous locomotives. The firebox had a combustion chamber and thermic syphons,the boiler had Elesco feedwater heater, the Baker valve gear had limited cutoff and actuated 14" piston valves.
Although they did encounter counterbalancing problems because of their small drivers, Drury (1993) reports that they reaped a 33% increase in speed pulling 44% more tonnage while burning 42% less fuel.
Procured in five batches:
Class Works Road Year Remarks
I-1 6959-6968 600-609 1925 60,000 lb axle loading
I-1-A 7237-7251 610-624 1927 60,600 lb axle loading
I-1-B 7297-7211 625-639 1928
I-1-C 7314-7328 640-654 1928
I-1-D 7428-7442 655-669 1929 61,400 lb max axle loading
Those that were upgraded with Timken roller bearings on all axles -- 608, 657, 666 -- were redesignated I-2 in 1948.