Baldwin supplied MAS Class 2-6-6-2 Mallet locomotive No. 460 to North Western Railway in 1923. Both the Mallet, and the Garratt No. 480 that came in 1925 from Beyer Peacock, were experimental, one-off locomotives that were tried between Sibi and Quetta on the Bolan section but both suffered wheel slippage and NWR resorted to the tried and tested pair of HGS class 2-8-0s, one in lead and other as a banker on its mountainous routes of Bolan and Khyber. The Mallet and Garrat were transferred to the less graded section between Lala Musa and Rawalpindi. The story goes that once a spanner was accidentally left in one of the low-pressure cylinders and that led to the untimely demise of this locomotive as there were no spare parts and no possibility of repair. (Ken Staynor)
See also the Garratt No. 480 of the NWR.