The South African Railways Class H 4-10-2T, introduced in 1899, was a steam locomotive from the pre-Union era in the Colony of Natal.

In 1912, after the establishment of the South African Railways, 93 of these Class C Reid Tenwheelers survived unmodified and were designated Class H.[1][2][3] By 1898, increasing traffic on the new Natal Government Railways (NGR) mainline into the interior, with its sharp curves and severe 1 in 30 (3⅓%) gradients, necessitated double-heading of the NGR's Dübs A 4-8-2T locomotives on the heavier section of the Natal mainline between Estcourt and Mooirivier as a means to run longer trains to reduce occupation of the line.

[2][3][4] Since there was no precedent for such an enormous Cape gauge tank locomotive, the design was the subject of some severe criticism and various objections were put forward against its introduction.

[4] In 1900, the General Manager of the NGR reported that the trials of the 4-10-2T Reid locomo­tive had proven successful beyond anticipation and that the engine could haul a gross load of 200 long tons (203.2 tonnes) over the worst section of line with ease, 50% in excess of that taken by a Dübs A locomotive.

When a locomotive classification system was introduced on the NGR, they were designated Class C.[4][5][7] To negotiate sharp curves, both the first and fifth pairs of coupled wheels were flangeless.

[2] The main shortcoming of the Reid Tenwheeler was a tendency to derail while reversing, particularly over points, since the trailing coupled wheels were flangeless and tended to drop off the rails in the 1 in 7 turnouts which were in use at the time.

[1][4][6] The Reid Tenwheelers were initially employed on the lower section of the Natal mainline and worked both passenger and goods trains.

When the Corridor Train was introduced between Durban and Johannesburg in 1903, the Reid Tenwheelers worked the trains between Durban and Volksrust, but their limited coal and water capacity necessitated en route engine changes at Inchanga, Pietermaritzburg, Mooirivier, Ladysmith and Hattingspruit.

[2] In the SAR era, some were relocated to De Doorns in the Cape Province for banking service up the Hex River Railpass.