▁into ▁three ▁separate ▁Class es , ▁according ▁to ▁wheel ▁arrangement . ▁Bear ing ▁in ▁mind ▁that ▁tend ers ▁could ▁and ▁did ▁migr ate ▁between ▁engines , ▁the ▁Type ▁SH ▁tend ers ▁should ▁have ▁been ▁number ed ▁in ▁the ▁number ▁ranges ▁as ▁shown . ▁▁ 1 9 0 4 : ▁N GR ▁Class ▁B ▁ 4 - 8 - 0 , ▁S AR ▁Class ▁ 1 , ▁numbers ▁ 1 2 4 5 ▁to ▁ 1 2 8 8 . ▁▁ 1 9 0 4 : ▁N GR ▁Class ▁B ▁ 4 - 8 - 2 , ▁S AR ▁Class ▁ 1 B , ▁numbers ▁ 1 4 4 0 ▁to ▁ 1 4 4 5 . ▁▁ 1 9 0 5 : ▁N GR ▁Class ▁A ▁ 4 - 6 - 2 , ▁S AR ▁Class ▁ 2 , ▁numbers ▁ 7 6 2 ▁and ▁ 7 6 3 . ▁ ▁Classification ▁letters ▁Since ▁many ▁tender ▁types ▁are ▁inter change able ▁between ▁different ▁locomot ive ▁classes ▁and ▁types , ▁a ▁tender ▁classification ▁system ▁was ▁adopted ▁by ▁the ▁S AR . ▁The ▁first ▁letter ▁of ▁the ▁tender ▁type ▁indicates ▁the ▁classes ▁of ▁engines ▁to ▁which ▁it ▁could ▁be ▁couple d . ▁The ▁" S _" ▁tend ers ▁could ▁only ▁be ▁used ▁with ▁the ▁three ▁locomot ive ▁classes ▁with ▁which ▁they ▁had ▁been ▁delivered . ▁ ▁The ▁second ▁letter ▁indicates ▁the ▁tender ' s ▁water ▁capacity . ▁The ▁"_ H " ▁tend ers ▁had ▁a ▁capacity ▁of ▁. ▁ ▁Mod ifications ▁and ▁re building ▁