This is from my draft book:
J.S. Innes Limited of Toronto created a rear tracked arrangement powered by the rear wheels, suitable for any 1½- or 2-ton chassis, long or short-wheelbase, with either freight or passenger body, though Ford chassis seem to have been the preferred choice. For winter use, the front wheels were exchanged for steering sleighs, though the front wheel system enabled the truck to proceed over any road or surface conditions other than presumably pure snow. The conversions seem to have been aimed mostly at Ford truck users though. ‘Innes-Cunningham’ half-track conversions were used by the DND [DEPARTMENT OF NATRIONAL DEFENCE IN OTTAWA]: a limited number of Innes-Cunningham half-track conversion Ford trucks were used as gun tractors with ‘C’ Battery, RCHA, Winnipeg, and with the RCAF as crash tenders with Ward-LaFrance fire pumper bodies in 1939. The Artillery trucks may have been 1936 Models; a Lt. Colonel C.R. Grant, DOC, MD No. 10, wrote to the Secretary to the DND concerning Innes-Cunningham Half-track vehicles for ‘C’ Battery, RCHA Grant referred to a letter of 6 January 1937 and his radiogram of 12 January. He enclosed a full report embodying the information contained under various headings of NDFC 763, complied by the Officer Commanding, ‘C’ Battery, and also a separate detailed report giving cost of repairs and replacements. The DND had several 1936 Model 2-ton Stake trucks and there is no indication as to which trucks were conversions, if any. It is thought that the 1936 half-track conversion as revealed on P. 17 of Dr. Gregg’s book ‘Blueprint for Victory’, which was purchased by the DND for trials at Petawawa, and was allegedly a Marmon-Herrington conversion, was one of at least two Innes-Cunningham conversions acquired in 1936
Another company that offered conversions to provide 6 x 4 drive was the THORNTON TANDEM COMPANY of 5128 Braden Street Detroit, who specialised in Chevrolet and GMC chassis, as well as Ford and Dodge. These used a patented rear bogie, and allowed twin rear wheels on each rear axle to increase capacity from 1½- to 3-tons. The Canadian representatives were across the river in Windsor: H.V. WELLES LIMITED, hence their ‘Welles-Thornton’ conversion