From the SMU Libraries collection: https://digitalcollections.smu.edu/digital/collection/jmm/id/1217/rec/36
Based on its location, I am inclined to believe that this is StLB&M 2115… Blt. July 1912 by GE Ninety one seats?, 52 tons Model CE70B11. To GCL 504 circa 1914, to MPL 1926. Will need to dig up my diagram book.