186

IM COLLIERY GUARDIAN.

January 23, 1914.

Wagons fitted with oil axleboxes should have a special
ticket clip (fig. 2) fixed on the solebar just above one of
the axleboxes, and a special card printed, as shown,
might be used.

The workman whose duty it is to attend to the oiling
could then see at a glance by taking the ticket out,
when the wagon was last oiled, and whether it was again
due for oiling. The owners’ traffic manager could also,
in case of a stoppage outside for hot box, ascertain by
whom the wagon was last oiled and when, and could in
this way bring it home to the party responsible if the
hot box was caused through carelessness.

In the case of a grease box, the feed holes should be
properly probed out, and the box filled with grease
before being sent out on a journey, attention also being
given to see that the lids of the boxes and the dust
shields fit tightly, so that no dust or dirt can get into
the grease when the wagon is in traffic.

In the case of oil axleboxes, they should be examined
by a competent man at least once every three months,
particular care being taken to see whether there is any
water or dirt in the oil; if so, this should be removed.
The pad should carefully be examined to see that the
feeders are not clogged; should this be the case a new pad
should be fitted. The workman should be supplied with
a simple syringe so that water can easily be removed
from the box. Many an experienced man is misled here,
as on looking at the front of a box he may see what is
apparently a full supply of oil, when actually it is water

Fig. 3.

Fig. 4.

with a covering of oil. If, by any chance, dirt has got
into the oil, the box should be taken off and thoroughly
cleaned out and then refilled with clean oil. Should the
pads be glazed or burnt they must be replaced, but new
pads should never be used unless they have had a 48
hours’ soaking in oil. The spare pads should be kept
in a warm, dry place, as the wicks readily absorb
moisture, this prevents the oil from thoroughly soaking
the wicks, and when placed in the box the pads are not
as efficient as they should be. The workman must be
careful to see that no dirt gets into the box whilst he is
examining it, and when fastening the lid he must
see that it is a good fit and water tight. Dust shields
which are badly fitted are the cause of a large number
of short brasses, owing to the dust and dirt which they
allow to penetrate to the wheel seat ends of the brass ;
care should, therefore, be taken to see that the shields
fit properly.

Some Practical Hints.

If the following hints are carried out they will largely
reduce the number of hot boxes :—

In fitting new brasses a very common fault is to give
too wide a bearing surface. Sometimes a man will fit a
brass so that all the bearing surface of same is in
contact with the journal, and instead of the oil or
grease being carried under, it is wiped off. The width
of the bearing along the length of the brass should not
be more than 1| in. wide ; this allows sufficient “ lead ”

for the oil to get between the brass and the journal. An
examination of a brass which has got properly bedded
down in use on a journal, will make the reason for
giving this “lead” quite clear. It will be found that
the radius of the bearing surface of the brass is larger
than the radius of the journal; the explanation of this
is that, as the journal revolves in the direction shown
by the arrow (fig. 3), the lubricant is forced into the

Fig. 5.

Fig. 6.

*to

Fig. 7.—Burnishing Tool.

Fig. 8.—Testing Apparatus.

b

t I

■

i

I

I

space B D and carried forward between the brass and
journal; the film is, however, much thinner from A to
C, and the brass gets worn more at this part. When
the journal revolves in the opposite direction, the reverse
action takes place, and it is this “ bedding down ” which
causes new brasses to run warm to begin with. It is
obvious that, by fitting the brass as shown on fig. 3, this
action will be accelerated. It makes it easier for the
workman to fit the brass properly if they are bored out
£in. larger than the diameter of the journal. The box

liners and the backs of the brasses on which these rest
should be perfectly level and free from rock. To ensure
this the surfaces H to L (fig. 3) should be accurately
machined.

It is the practice of some builders not to machine
these liners or the backs of the brasses, but, if satisfac-
tory results are to be obtained, it is essential that this
should be done, otherwise there is overloading on some
particular portion of the brass, with local heating, and
consequent hot box. To illustrate this point it may be
mentioned that in February 1911 the Railway Clearing
House issued drawings showing alterations to the axle-
boxes and brasses, which were designed to give the brass
a larger grip of the journal, so that during shunting
operations the journal would be prevented from striking
and breaking the sides of the axleboxes. The brasses
at first gave some trouble by running hot, and on
examination of some of these cases it was found that
the bottom of the grease chamber and brasses had not
been trued up, and the brasses were found to be clipping
the journal as shown in fig. 4. The brasses ran cool
after the backs were trued up. Care should also be
taken to see that the brass, when in position in the box
has sufficient play at the sides, as shown in fig. 5. This
will enable it to take up its proper position even if the
box has not been cast perfectly square.

In the case of brasses which run in oil, the best
practice is not to put any holes through the crown of
the brass, as, if this is done, the continuity of the film
between the brass and the journal is broken, and the
lubrication is not as efficient as in the case of a brass
which has not top feed holes. It must be remembered
that the. oil pressure between the brass and journal is
about 300 lb. per square inch, and the top feed holes
allow a certain amount to escape from the most efficient
bearing area.

In some designs of boxes the syphoning top feed is an
advantage; but when this is used, channels should be
put down the outside edge of the brass to allow the oil
to run on to the journal (see fig. 6).

When attending to a hot box the workman should
never be allowed to file a journal as it is impossible for
him to get a proper surface and keep the journal true;
also it is very probable that a wagon which has had the
journal filed will only run a few miles before the box
will again require attention. The best plan, therefore
if the journal is cut, is to change the wheels and have
the journal properly turned and burnished up in the
works.

In the case of wheels which are kept for emergencies
of this description, the journals should be painted with
a mixture of white lead and tallow to prevent them
going rusty, as immediately a journal gets the slightest

rust on it the proper surface necessary to good running
is destroyed. Owners and repairers do not give this point
the attention that it deserves. The wheels are allowed
to stand in their yards or shops unprotected from rust,
and any stray blows which are likely to damage the
journals. When a replace set of wheels is required for
a wagon stopped away from home the rust is cleaned
oft with emery or a file, by which means a proper
surface cannot be produced. The best plan is properly
to protect the journals by a covering immediately they