735 Riddle Road Cincinnati, Ohio 45220
In 1904, William Fletcher published English and American
Steam Carriages and Traction Engines. A master mechanical
engineer, Fletcher designed engines at various times for the
British companies of Clayton & Shuttleworth and Ransomes, Sims,
and Jefferies. His 428-page book (published by Longmans, Green, and
Company with offices in London and New York) offers insight into
how a British designer viewed American traction engines.
Fletcher believed that English engines of the late 1800s and
early 1900s were built slightly heavier than most of their American
counterparts. British designers wanted their traction engines to be
perceived as ‘all purpose ‘good for hauling over relatively
long distances and for belt work. Also, English threshing machines
were notoriously bulky; only a sturdy engine could pull such
threshers over muddy country lanes.
In Fletcher’s day, the thickness of the boiler plate of the
typical English engine surpassed that of an average American
engine. Most of the plate used in British boilers was between
seven-sixteenths and one-half of an inch thick, and the plate in
those portions of the firebox exposed to the greatest heat might be
even thicker. As Fletcher reported, the boiler itself was often
shorter and slightly wider in diameter than was customary in an
American engine. This factor might help to account for
Fletcher’s assumption that British engines were ‘quick
steamers.’ Like the boilers, English fireboxes tended to be
short and not too deep. The fireman (or stoker) had to hope for
coal (and coke) of a high quality! In most British makes of
engines, fireboxes used a sliding door, not the hinged doors common
on American fireboxes.
The diameter’ of the tubes in British boilers usually
measured one-fourth of an inch wider than that of tubes in the
average American boiler. With larger tubes, fewer were needed than
was normal among American makes. According to Fletcher, British
designers did not want a great many tubes because they wished to
provide as much steam space above the water line as practicable.
The proportionately lower water level in an English boiler might
explain the property of getting steam up quickly.
British designers often employed cross-compound cylinders for
plow engines, road locomotives, rollers, and showman’s engines.
Single-cylinder engines served agricultural and general purposes,
but double-simple and tandem-compound cylinders were as rare as
hen’s teeth. Fletcher argued that a double-simple arrangement
wasted steam. For their cross-compound cylinders, English designers
preferred center-cranked engines, as a glance through Floyd
Clymer’s Album of Historical Steam Traction Engines
will corroborate. Most British cylinders rested within a large,
sturdy jacket. As steam direct from the boiler rose to fill this
jacket, and as it was this steam which entered the steamchests, one
could say that this jacket replaced the steamdome. Indeed, English
engines seldom were equipped with a dome, while American boilers
almost invariably had one. Although certain English designers
placed the steamchests on the sides, thereby making it easier to
gain access to the valves, most located the steamchests on top of
the cylinders and well within the large jacket. This arrangement
served to improve the engine’s efficiency.
Fletcher points out that mechanical engineers in Britain tended
to locate their cylinders next to the smokebox because they felt
certain that the driest steam could be found there. They piped
steam directly from the front end of the boiler into their
cylinders. With the steamjacket acting as a kind of dome, the
English engine had virtually no exposed steam-piping. For
additional economy of operation, boilers routinely sported
jackets.
Certain British builders slanted the valves downward from the
top of the tall steamjacket toward the crank shaft (considerably
complicating the engineering of the design). With such valves
tilted above horizontal cylinders, the ports on the ‘high’
end had to be wider so as to prevent wire drawing of the steam on
that end. ‘Wire-drawing’ meant that the frictional
resistances in a poorly-de signed port (usually a long and
constricted one) tended to throttle down the steam, thereby
decreasing power.
Fletcher noted that his English colleagues staunchly favored
rear-geared arrangements; that is, British designers opposed
locating the driver wheels in such a way that the hubs would line
up with the center of the sides of the firebox. Rather, they
insisted that the best distribution of weight occurred only when
the drivers were located on an axle running across the firebox at
about the level of the platform. Fletcher and his con temporaries
did not want the front end of their engines to lift off the ground,
and they accused certain American builders of installing heavy
water tanks in front of the smoke stack so as to weight down the
front end of side-geared engines. Fletcher claimed that some
American companies made the bottom of such front-mounted tanks from
two up to five inches thickmerely to add weight!
With driver wheels on an axle be hind the firebox, British
engines featured long connecting rods to reach from the steamjacket
and cylinders at the smokebox end to the crankshaft at almost the
opposite end of the boiler. While such a longer (and heavier!)
connecting rod in a center-cranked engine smoothly applied power to
the crankshaft, the extra weight in the reciprocating parts tended
to slow down the engine. Also, the additional length caused the
piston to run more slowly than that in an equivalent American make.
The average English engine topped out at 160 revolutions per
minute, while the ordinary American engine ran at 250 r.p.m.
English designers often employed a rather complicated system of
levers to reverse the engine and to ‘hook it up’ so as to
use steam expansively. Arranged in a linkage, these levers
accomplished the work which eccentrics and rods did for most
American engines. Occasionally, these levers attached to the sides
of the connecting rod.
A high percentage of English engines adopted the practice of
using four shafts: the crankshaft, the axle of the driver wheels,
and two countershafts in between to spread out the gearing and to
lend strength. To with stand the strains of hauling massive loads
over poor roads, British driver wheels were made heavy. Preferring
flat steel spokes, English designers made the diameter of their
driver wheels approximately eight to ten inches larger than that of
American drivers. Such wheels helped to add weight. Quite often,
the compensating gear (or differential) was located on the axle,
not on one of the countershafts. By employing two counter shafts,
British engineers could keep more of the gearing inside heavy
sideplates (which extended upward from the boiler and backward
beyond the firebox), could leave room on the crankshaft for an
eccentric-driven water pump or similar device, and could produce a
thinner engine over all! A British law prohibited wide
engines.
Numerous English engines boasted winding drums and one or more
rollers for steel-wire cable. Certain builders bolted the winding
drum to the compensating gear. By pulling out a pin, the person
running the engine could disengage the driver wheels, and only the
gears and cable-drum would turn. Cables came in handy when
encountering steep grades. The engine could be parked at the top of
the hill and could wind the cable to pull up a wagon, threshing
machine, or other load from be low. Designers customarily attached
rollers to the left side of the tender (as viewed from standing
behind the engine).
In general, British builders disliked friction clutches.
Instead, levers served to mesh gears. The person running an engine
had to make sure that the gears were in perfect alignment before
using a lever to shove them together. On the other hand, English
engines (unlike their American counterparts) routinely had brakes.
The device looked like either a steering wheel on a vertical shaft
or a tiller located near the back of the tender. English engines
nearly always included gearing for two speeds on the
roadoccasionally three speeds. Such engines could pull themselves
along the ground more rapidly than most American engines. Although
the A. W. Stevens Company of Marinette, Wisconsin, built one of the
fastest traction engines in the United States, it attained four and
a half miles per hour while British makes routinely accomplished
five miles per hour.
In 1870, Aveling and Porter built engines having heavy
sideplates (called ‘hornplates’) which carried the bearings
for the crankshaft, countershafts), and axle. As soon as Aveling
and Porter’s patent expired, other British makers adopted this
system of sturdy hornplates, which, along with shields for any
gears located outside the hornplates, not only prevented dust from
cutting the gears but also concealed the moving parts from the eyes
of nervous horses. Most English engines which were in tended for
haulage on highways used a solid flywheel for the same purpose; the
government had imposed restrictions on builders to prevent engines
from scaring skittish horses. Fletcher thought that any moving
vehicle whatsoever would frighten a nervous horse and that
owners of such excitable horses had no business thrusting them into
the public thoroughfares. Incidentally, early steam carriages often
resembled horse-drawn carriages not because designers lacked
imagination but because the builders hoped to pacify horses, which
might recognize and not fear the outward appearance of a
carriage.
The flywheels of British engines tended to be much larger in
diameter but smaller across the face than those of American
engines,. Typically, the diameter of such English flywheels
exceeded that of American ones by twelve to fourteen inches. The
good-sized flywheel helped to smooth out the movement of the
engineespecially while in traction gear. On the road, British
engines tended not to use their governors. Most were equipped with
a crossarm governor, located perhaps far back from the cylinders
(not on the steamchest, as was generally standard in American
custom).
Almost all English engines boasted a double-formed safety valve,
found on top of the steam jacket. This ‘distinctively
British’ design was known as a Ramsbottom valve, named for its
inventor. Emphasizing safety, most British engines carried two
glass water-gauges.
Fletcher analyzed the ‘latest types’ of American
traction engines; while maintaining objectivity, he permitted
himself a few pointed comments. After quoting an advertisement from
the Advance Thresher Company which stated that ‘in beauty and
simplicity of design, the Advance engine is beyond each and every
one,’ Fletcher remarked, ‘Our readers will form their own
opinion respecting the engine and the claims made for it.’
Turning to a Case engine, Fletcher observed that the rear axle and
countershaft were arranged ‘as in English practice’ and
that hornplates supported the crankshaft ‘again … following
English design.’ Fletcher applauded Frick’s decision to
discard what he called the ‘over-neck disc-crank’ and to
choose ‘with advantage’ a center-crank mechanism (or
‘counterbalanced dip-crank,’ in Fletcher’s
nomenclature). When Fletcher described the O. S. Kelly
Manufacturing Company’s engines, his objectivity waned:
‘The traction engines made by this firm differ from all the
American examples which we have thus far de scribed. They have
advantages not possessed by the others …’ Small wonder! Kelly
engines closely resembled their British counterparts.
While engines from both sides of the Atlantic enjoyed more
traits in common than Fletcher or anyone had the right to expect,
distinctive qualities imparted a decidedly British appearance to
engines from Shake speare’s ‘scepter’d isle’ and
gave to American engines a look befitting Uncle Sam. In Great
Britain and the United States, numerous enhancements awaited steam
engines after Fletcher’s 1904 publication date, but his book
comparing English and American engines affords modern readers a
keen, clear view of the remarkable industrial ingenuity of his
day.
Note: This article uses ‘English’ and
‘British’ synonymously. A few builders of engines existed
in Scotland, none in either Wales or Ireland.
