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I found an interesting article in a copy of Railway Signal and Communication. This shows the track layout at Mescal during the early 1930s. In 1926 SP added a US&S interlocking at Mescal, AZ. The unit was in the old EP&SW station and had 9 levers to control switches and 8 levers to control signals, plus one lever to control the lock on a hand operated switch. West of Mescal the SP used the EP&SW track for westward trains and the original SP line for eastward trains. The EP&SW line bridges over the SP line at the east end of Mescal. Connector tracks were added so trains could use either line east of Mescal. The diagram makes it look like the SP and EP&SW lines are fairly close together. In reality the lines were about 200 feet apart in the station area.
Engines 9058, 9172, 8655, and 9170 lead a train passed the Mescal coaling tower on February 1, 1974. I think these coaling towers (Tuscon, Mescal, Bowie, Lordsburg and Deming) were built in the late 20s after the SP acquired the EP&SW. Part of the EP&SW agreement was that the SP would use coal from the Dawson Mine in New Mexico. With an online source of coal it must have been cheaper to run coal fired instead of oil fired locomotives between Tucson and Tucumcari. The Dawson Mine ran out of coal around 1950. The 12 coal fired 3800 class 2-8-8-4s that ran almost exclusively between El Paso and Tucumcari were converted to oil in 1952 and moved to the Modoc Line. Unfortunately for railfans, the semaphore signals were replaced in November 1995 and all the coaling towers including this one at Mescal were torn down by the end of March 1998. I was able to video tape some trains in the area in April 1995 before UP took over and things changed forever. There is now a double crossover about 1,500 feet west of the highway crossing and double track extends east all the way to El Paso. Disk 56