TRAMMING AND CENTER-MARKING.
What is technically termed "tramming" consists in so adjusting
the driving wheels that they shall stand square with the frame of the engine.
It is generally done when repairs are being made in the shop, but it is
important that every Engineer should be familiar with the expeditious mode
of doing it. When the driving wheels are taken from under the engine, the
distances are equalized both ways from the face of the blind wedge of the
forward main box to the male casting which is fastened to the smoke box,
between the cylinders, and in the center of the boiler. After the blind
wedges to the forward driving boxes are trammed, all the driving boxes
being ready, they are place in the pedestal or jaws of the main boxes,
and the center of the boxes being obtained, the back wedges may be adjusted
by tramming from the center of the forward driving box to the center of
the back driving box, thus equalizing the distance of both main centers
on both sides of the engine.
Much trouble is often avoided by having an engine properly center-marked.
This is done as follows: After the blind wedges to the forward boxes have
been trammed and put in place, then tram from the face of the blind wedge
of the forward driving box to the outside of the pedestal or jaw to which
the blind wedge is fastened. Tram as far back from the face of the wedge
as possible, and make a prick punch mark on the pedestal, using the same
tram for both sides of the engine, taking care that the distances from
the face of the wedges to the marks on the jaws are alike on both sides.
Tram from the middle of the jaws. When engines get out of tram, as they
do frequently, the center marks may be used to adjust the machine without
raising it off the driving wheels. The forward driving wheels should be
trammed first from the center marks and then made to serve as a guide for
the rear drivers. Particular attention to this matter is essential to secure
the easy working of the locomotive and the avoidance of hot crank-pins
and similar drawbacks.
1 - Introduction
2 - Locomotive
3 - The Fireman
4 - Advice to Young Engineers
5 - Tramming and Center Marking
6 - Adjusting Side and Main Rods
7 - Pumps and Pump Valves
8 - Cylinder and Cylinder Packing.