All of the mikes have the same sized driving wheels but the dimensions of the cylinders became larger on each new order of locomotives. Total weight increased to, the 12 weighs 112,000 pounds while the 14 and 15 weigh around 150,000 pounds, the 17 on the other hand weighs over 163,000 pounds. The 17 was the next to last steam locomotive purchased, and it came to the EBT in 1918. The identical #18 store inoperable inside the house was purchased in 1920. The #16 is also stored inside the house and it to is inoperable. The roster never had a #13.