In the middle 1950s, the Montreal Terminal’s Iberville shops proposed a radical new style of steam engine so that the MTRR could continue to economically operate steam. What they proposed was a steam engine that was fairly common in Europe, Asia, and Africa, but completely unknown in North America: a Garratt (a Beyer-Peacock design, licensed to Alco, then sublicensed to the Montreal Terminal) double-10 wheeler. (Designated as class Ω, because even the MTRR could see the writing on the wall and – correctly – guessed that this would be the last opportunity to build an experimental steam engine.)

When #20 was outshopped in 1958, it had a water-tube boiler, which very quickly went the way of all such boilers and was replaced by a conventional fire-tube version, but was quite successful (in terms of pulling trains) with both boilers.

After the crews stopped being revolted by its looks, it became one of the most loved steam engines on the railroad and the MTRR proposed building a small fleet of Garratts to replace most of the bigger steam on the road. Alas, this was not to be the case; the wheels of the PV&T+LT&L+MTRR merger were in progress, and steam was not on the roadmap that the railroad planned to follow.

In 1962, the merger was completed and the MTRR’s steam fleet was swiftly replaced with diesels; #20 was one of the first locomotives to be retired (never making it onto the PV&T’s unified roster) and ended up being stored in the erecting shop for many years, then went up to St-Constant to join the historical fleet.