Evening star. [volume] (Washington, D.C.) 1854-1972, 1898-01-08
CONTINUOUS RAILS,
How the Effect Of Contraction and
$780, Expansion is Manifested.


People who have watched the busy gangs
OF men engaged in preparing for the in
stailation of the underground electric sys-
tenn on the Capital Traction railroad have
no doubt been interested in the process
followed In welding the rails The result
OF this process, as is well known, is a con-
tlnuous rail, over which the cars rove
with greater smoothness than over tracks
composed OF separate rails. as the work
OF welding Is done on the street. some de-
talis are perfected in the open air inyoly-
ing processes which are usually followed
only under roof
Inc old joint is first taken off the rails.
then the dirt and rust on the rails are
thoroughly removed. A piece of iron is
driven between the ends of the two rails
wedging them tightly and bringing them
to the true line and grade A mold of
cast iron is made in halves, about fifteen
lnches long and three or four inches wide
Whlch are clamped together at the Joint
eand Is tamped around to avoid any leak
age OF the metal, and then the molten
metal, obtaiEed from pc rtable furnaces. is
poured into the mold. In two or three
minutes the mold is removed, leaving the
JOINT impact ABOUT the rail. After cooling
any unevenness on the rail is filed of
and then the process of welding is finished.
II IS, OF course, understood that iron
rams expand and contract under fnduenc.,
OF tne temperature of the air, and no doubt
great many people wonder how this
welding of the rails is consistent with this
established law of metals
1t Is found as the result Of experiments
mat In case of iron rails imbedded in con-
crete and fastened on iron yokes as is the
case with the rails on this road, that the
contraction and expansion of the iron is
connned to the sectional area Of the rail.
some interesting experiments were made
by Mr.. A. j. Moxham at Johnstown, Pa,
In regard to the effect of temperature on
continuous rails, and the results of his OBJ
servation were given in a paper which was
read several years ago before the American
Street Railway Association. The conclu-
sions reached by Mr.. Moxham are as fol-
lows:
The experiment has proved absolutely
and beyond cavil that 1t the raiD is re-
strained and held by the surface friction
Of the surrounding roadbed. From first to
last, from temperature Of % degrees be-
low freezing point Tor 10 degrees) to a
temperature of 30 degrees above freezing
point Tor 121 degrees), extending from
March to August, there was absolutely no
movement of the track out of place. Even
at the ends was this true; proving that not
only will the roadbed hold the track as a
complete structure, but that 1t will do it
consecutively. Once bedded, 1t will hold
rail ten feet or thirty feet. as we'll
!, 100 feet. On this point there is no room
for error. The expansion in 100 feet. il
not neutralized, would equal 81 inches,
under the conditions here stated, and 81
inches would throw the rail out of line
fourteen feet, If it were held at the ends
and permitted to bow in the center. An
expansion of one rail would mean about six
inches in thirty feet out of line. The query
arises. What has become of it?' 1t is
existent and. like all force. it would flow
to the point Of least resistance. In case of
a street rail. buried in the roadbed. it Is
reasonable to believe this point is in
minute enlargement and reduction Of the
sectional area of the rail-