Mike Feeney, at skyviking.net, states that the Canadair C-4/DC-4M North Star/Argonaut did indeed have reversible pitch propellers. Equipped with Hamiltion-Standard "Hydromatic" propellers, the props had the fine-pitch stops moved so as to enable reverse pitch.
Mr. Feeney also concludes that, after considering a myriad of operational conditions, TCA was correct in selecting the Rolls Royce Merlin engine, as a C-4 powered Merlin was 30% faster than the radial engine powered DC-4, plus the Canadair DC-4M had a much higher service ceiling and a lower specific fuel consumption, given a higher power setting. Note that the 622 Merlin was more robust than the war-time Spitfire Merlin. Regardless of Rolls-Royce's efforts in bolstering the Merlin for TCA, after the first year of airline service, it became obvious that the Merlins were maintenance intensive. TCA warranty claims resulted in RR agreeing to produce a quantity of 622 Merlins at a reduced cost as compensation.
For block-to-block times and specific fuel consumption rates, an early Douglas DC-6 is a fair comparison to the Canadair DC-4M. (Bets are off in tropical climes and in a -40 Edmonton cold start).
Cost-per-mile determination? Nearly impossible, as most BOAC Argonaut flights and some early TCA North Star flights were all first-class configuration, complete with berths, hot meals served on porcelain china and silver-ware, plus the services of a purser! Navigators, Radio Operators and the occasional Engineer were de rigueur aircrew as well.. In the mid-fifties, TCA reconfigured several North Stars to a denser all-coach (economy-class configuration) for inclusive Canadian trans-continental service, with a two-pilot and single stewardess aircrew being standard.
In rain, sleet, snow, heat and lightning, the North Star performed yeoman service on many regional high-density routes, such as the Toronto-Montreal; Toronto-Ottawa-Montreal; Toronto-Chicago; Montreal-New York; and the ever popular Toronto-New York route.
Below is a photo capturing a classic 3-bladed, cross-over exhaust mod, "TCA North Star", in the twilight of her long and arduous career. Sitting on a snow covered apron in the deep dark cold of a Canadian winter, (circa 1959-60). 10 years previous, she was deemed the fastest way to cross the Atlantic. Now she awaits, perhaps for the last time, a load of passengers she will fly to Chicago-Midway... after which her interior will be gutted and converted into freighter configuration. Few, if anyone, will lament her passing..
