The H-Series was intended to be an eventual replacement for the 40S in the same way that the U had been intended to replace the 60S, but the H proved too expensive and in the end only five were built. The H-Series looked similar in style to the U-series but it was much shorter and had the feature of a fold-up driving well so that the loco could be lowered down a mineshaft with ease.

The first H-Series was ordered on 23rd February 1968 and was intended for British Newfoundland Exploration Ltd., Badger, Newfoundland. It was to be gauged to 2-ft but the wheelsets were to be convertible to 2-ft 6in or 3-ft gauge if necessary. This first loco was allocated w/n 100H001 but did not receive this number as the order was subsequently cancelled. It appears that this first loco, or what existed of it at the time, was used to fulfil an order from the British Aluminium Co. Ltd. for their 3‑ft gauge Lochaber works line in Scotland. Changes were made, which included the fitting of a passenger seat, cab, and a hydraulic power-take-off in the form of a Dowty pump and snap-on flexible hoses. This was suitable for an Atlas digger or a  cu. yd. end-tipping wagon. The works number given when it left the works was 105H006 although some records also refer to it as 105H001.

The four 100H type locos were sold through dealer Jarvis Clark Co. Ltd. for INCO, Thompson Mine, Canada and were also capable of being regauged from their initial 3-ft down to 2-ft, or 2-ft 6-in gauge. As they were intended for mining use, they were fitted with Oxy-France exhaust scrubbers and fail-safe air brakes. The power unit fitted to the 100Hs was the Deutz F3L812(W) of 29 B.H.P. at 1800 R.P.M., whereas the 105H had a Deutz F3L912 of 37 B.H.P. at 2300 R.P.M. All used hydrokinetic transmission in the form of a Brockhouse torque converter. The wheels used were the same 18-in diameter pattern as used on the 40S/60S and the drive to the axles was by chains. The price of a new H-Series locomotive in 1969 was 2431.0s.0d.

Number Series (built between 1968 and 1969)

100H 002-005.

105H 006.