That the 70 was even built is a bit of an anomaly. She's a late (1922) example of an earlier (1912) design. There was a significant advancement in steam technology during those intervening 10 years and it was the widespread use of Superheat. However, this design did work out alright for Polson and later Rayonier. It's just that everything else being equal, she will use more water and fuel than a comparable engine with Superheat like 2-8-2T 17, which has the same diameter drivers and same size cylinders. No doubt though that she'll be a lot of fun to operate and ride behind.