No hydraulics used in any of the mills. The old mills used screw
jacks, mostly manually cranked to lower the rollers. Roller
stands were run off a line shaft using massive mechanical
clutches, then fed to a gear reduction to drive the rollers. Each
stand in a series of roller stands has to run faster than the
last since the metal has been squeezed smaller and longer. A big
issue in running the mill is to make sure the each roller stand
is adjusted to match the speed of the next roller down the line.
Any mismatch and you get bulging or pulling.

As an aside, take a look at the profiles for the various "I" beam
and channel iron stock. Example: an 8" I beam of any weight has
the same inside flange to flange dimension as all of the 8"
channel products. They had one size of roller to roll the
channel, adjusted the rest of the machine to make the web thicker
but not the flange thicker. The result is that the heavier beams
are not very ecomincal for their strength. Too much metal in the
web, not enough in the flange. But that was somewhat ok since
most of those beams where rivited into larger beams with the
ubiquous cross hatch straps seen on old bridgres. That put the
metal on the outside of the shape where it needs to be for max
strength to weight ratio.

One more thing to mull over: the size of beams has increased over
the years. The largest beam listed in my 13th edition Machinery
Handbook from 1946 is 120 pound per foot in a 24" beam. Modern
mills will do triple that per foot. Bigger equipment.

ED ROGERS wrote:
Thanks gentlemen for your replies.I didn't know the power source for the
rolling mill and how it was capable, with the technology of the day,in
exerting the high pressures to form the rail.Did they use hydraulics to
get the pressure applied?