CLASS: P1d-P2k - Mikado Type 2-8-2

Text taken from Spanner Magazine, Collectors' Item - 14 by' Omer Lavallée

In the evolution of the steam locomotive, effort was directed to produce an ever more powerful mechanism, within the fixed conventions of height and width peculiar to railways.

One of the limiting factors in a steam locomotive's ability to travel quickly was the rate at which its boiler could generate steam. As long as speeds remained low, comparatively small boilers sufficed, but as the demand for improved speeds arose with advances in track and roadbed, greatly enlarged boilers became necessary. Boilers were therefore made longer, and the additional length accommodated on a swivelling trailing truck placed under the firebox, the latter no longer confined to the narrow space between the driving wheels.

While trailing trucks began to make their appearance under passenger engines on Canadian Pacific lines as early as 1905, the large number of 2-8-0 type engines in freight service postponed development of a large-boilered freight locomotive until 1912. In that year the first 2-8-2 locomotives were produced (class P-1-a) and while they had the same tractive effort as N-2 class 2-8-0s then still being produced, their larger boilers meant faster steam generation and hence, higher speeds. The era of the fast freight train had come, and in spite of evolution toward a "super" locomotive which manifested itself in the 1920s and 1930s, the 2-8-2 remained the basic road freight locomotive to the end of the steam era, certainly on Canadian Pacific lines.

In all, 334 2-8-2s served the Company. Their American type name "Mikado", incidentally, was related to the fact that some 2-8-2s built for the Imperial Government Railways of Japan were said to be the first of their wheel arrangement ever outshopped.

Canadian Pacific's units proved to be most reliable and versatile engines; the light P-1, illustrated above, was equally at home on passenger trains in hilly terrain. Between 1926 and 1930, the ninety-five P-ls were rebuilt with smaller diameter cylinders and higher boiler pressures; as each locomotive was converted, 100 was added to its road number. Thus, No. 5018 illustrated above eventually became No. 5118.