Re: Rio Grande Southern #20

By 1899 using steel in boilers was standard practice.

In fact, the engines that became the C-17 class built in 1887 seem to have had steel boilers - rated at 145 lbs like the iron ones of a few years earlier. When the 1911 boiler inspection act came along requiring all boilers to meet a factor of safety of 4, the 1887 steel boilers were deemed worthy of remaining in service, but the iron ones would have required a significant reduction of boiler pressure to remain in service. So, the iron boilers got replaced with new steel boilers of butt-strap construction rated at 160 lbs. While the "C-17"s - to-be" stayed in service with steel lap seam boilers rated at 145 lbs.