CN LINES V12N3 - Canadian National Railways Historical Association

stemmed, largely, from the status of the
Canadian National as a post-First World
War amalgam of a number of failing or
undermaintained railways. Eight drivers
spread a locomotive’s weight enough that
the seemingly endless miles of less-thanperfect
hinterland trackage could be navigated
with a minimum of peril. Canadian
Pacific, on the other hand, with its comparatively
better infrastructure, embraced
the 4-6-4 as its latter-day heavy passenger
wheel arrangement of choice (the CNR,
by contrast, rostered only five Hudsons).
CNR+NRC=6400
Design work on the streamlining for
Canadian National’s U-4 locomotives had
begun in 1931—well before the New York
Central’s Commodore Vanderbilt made its
widely publicized debut as North America’s
first streamlined steam locomotive—with a
series of wind-tunnel tests conducted on
models at the National Research Council
(NRC) in Ottawa.
The Assistant Director of the NRC’s
Department of Physics, John H. Parkin,
assigned the task to physicist and aerody-
Retained after retirement as part of CN’s historical collection, U-4-a No. 6400 was
cosmetically refurbished in 1967 before it was conveyed to the National Museum of Science
&Technology in Ottawa. It remains a static showpiece at the renamed Canada Science &
Technology Museum.—CN photo
namicist Dr. John J. Green. Both men
were at the fore of the emerging discipline
of aerodynamics. Parkin, a University of
Toronto graduate in mechanical and electrical
engineering, had taught at the
University between 1912 and 1929, during
which time he gave Canada’s first
aeronautics courses and also supervised
the UofT wind tunnel. Upon joining the
NRC in 1929, Parkin oversaw the aeronautical
research undertaken by the
Council. Dr. Green joined the NRC staff
in 1930 after receiving a PhD in aeronautics
from London University. Both men
went on to particularly distinguished, yet
often intertwined, careers. Parkin was
instrumental in the founding of what
became Canada’s National Aviation
Museum, with Dr. Green a strong advocate
as well. During the Second World
War, Dr. Green became the Royal
Canadian Air Force’s chief research engineer
and a test pilot, contributing, along
with Parkin, to such ground-breaking
aeronautical efforts as the NRC/RCAF
“Tailless” flying wing of 1945-48.
It was perhaps ironic, then, that a locomotive,
and not an aircraft, would be one
of the earliest examples—and most enduring
legacies—of Parkin and Green’s NRC
work. Using a pair of 1:12 scale models of
the CNR’s most recent 6100-series U-2-c
Northerns—one a detailed model made
of steel and the other a simpler wooden
affair—Dr. Green developed several
potential shroud configurations in conjunction
with CNR motive power officials.
The railway, and the government,
had imposed a number of restrictions on
the NRC’s streamlining freedom, ranging
from the placement of safety appliances
and a desire to keep running gear uncovered
to the goal of achieving the greatest
aerodynamic benefit with the minimum
possible cost and complexity.
The objective was more practical than
esthetic: to reduce or eliminate the tendency
of smoke to obscure vision from the cab
while the locomotive was “drifting,” when
low speed and ambient air currents could
combine to blow exhaust smoke down
over the boiler and across the cab.
In a progression of modifications to the
wind-tunnel models, Dr. Green added a
hemispherical nose, then a “skyline” casing
to conceal the various domes and turrets
atop the boiler, then altered the skyline and
the angle of the cab front, and added a
teardrop fairing around the stack. The next
12 CN LINES