Maintenance of Coaches and Wagons
The prescribed economic lifespan
of coaches and wagons is 30 years and 40 years, respectively. Coaches and
wagons go through cycles of periodic maintenance in order to ensure that they
are in good working order throughout their lifespan. As stated earlier, the
basic principle followed under the preventive maintenance system is that the
equipment should be paid the necessary attention so that there is no wear and
tear and consequent deterioration and the wagons do not become prone to
failure. Some of the principles followed under such a scheme of planned
maintenance are outlined here.
implementation of the scheme should be as simple as possible involving minimum
amount of paperwork.
maintenance schedule must be prepared for every item that requires planned
(c) When the
schedule is executed, a brief description of the action taken, the
type of labour employed, and the time taken should
be noted down. Preventive maintenance, as applied to coaches and wagons on the
classified under the following heads.
overhaulling in workshops
and breakdown maintenance in carriage and wagon depots or sick lines
repairs at terminals or yards
1 Periodical Overhaulling in Workshops
Coaching stock is periodically
overhauled in workshops at prescribed intervals based on the type of service
for which it is used. The frequency of POH varies from 12 to 24 months. Such an
overhaul consists of lifting, which involves a thorough examination of all
components, and the execution of such repairs as may be necessary to enable the
vehicle to remain in service until the next periodical overhaul. The prescribed
intervals for the periodical overhaulling of goods stock are presented in Table
Table 24.9 Periodicity of POH of
2 Schedule Maintenance
The maintenance of different
types of rolling stock as per approved schedules is described below.
Between consecutive overhauls,
coaches are serviced in coaching depots on the basis of a schedule known as intermediate
lifting. This is normally done after six months of the date of the last POH
or lifting. During the process of lifting, trolleys, underframe members, the
body and floor of the coaches, etc. are thoroughly examined and the necessary
repair and replacement of the components of the running gear are carried out.
The side bearer/centre pivot oil is also replenished. Similarly, coaching stock
fitted with plain-bearing axle boxes (as distinguished from roller-bearing axle
boxes) undergo the process of 'repacking' at general periodicity as follows:
express train coaches Two months
train coaches Three to
coaches Four to six months
All axle boxes with bearings of the entire goods stock are
periodically repacked at maintenance depots according to prescribed schedules.
In addition, the axle boxes are packed whenever a wagon is lifted off its wheels.
Roller-bearing axle boxes are attended to in workshops during overhaul
Coaching and goods stock
There are a few schedules that
are common to both coaching and goods stock. Some of the important maintenance
work done in compliance with these schedules is the following.
brake cylinders The vacuum brake fitted on the stock must be overhauled
at intervals of 18 months in the case of coaching stock and 18 to 24 months in
the case of goods stock. Normally there is a separate section for vacuum
cylinder overhauling in the maintenance depot.
boxes The axle boxes (plain-bearing) of coaching and goods stock are
oiled periodically. The coaching stock on passenger trains is oiled every
15 days. A goods stock with permanently secured face plates must be lubricated
with at least 225 g of oil per axle box at intervals of one month, either in
maintenance depots or in the originating/terminating yards.
(c) There are
many other scheduled maintenance works such as alarm chain apparatus testing,
tank wagon valve testing, water tank painting, etc., which are implemented in
the maintenance depots at the prescribed frequencies.
3 Breakdown Maintenance
The maintenance depots attend to
all the breakdowns or failures of the rolling stock. Breakdowns are unusual
incidents resulting either from human failure or due to the failure of the
equipment. Some of these breakdowns even result in accidents.
The most common failure of a
coach or a wagon is the one that occurs as a result of the axle box heating up
in the course of the run, popularly known as 'hot box'. Every journal (the part
of the axle at its ends, which bears the weight of the wheels) that becomes hot
during the run of the train, thereby necessitating the detachment of the coach
or wagon from the train before it can reach its booked destination, is
considered a hot box.
There are many other kinds of
breakdowns which must be attended to in maintenance depots to ensure the safely
of the wagon or box.
(c) Bent sole
Maintenance at Terminals and Yards
The rolling stock is on the move
most of the time. Since the major scheduled maintenances such as overhaulling
are done only when due, and call for the temporary immobilization of the stock,
the normal maintenance of the stock is done in the course of its service at
terminals and yards.
This maintenance mainly involves an examination or inspection
of the coaches or wagons of the train and is carried out in two stages.
Stage I: At the approach to the terminal or yard
when the train is still in motion.
II: At the terminal or yard where the
train normally stops.
The first stage of the inspection
helps in discovering those defects of the under-gear that are indicated by
unusual sounds or disjointed/broken hanging components. For example, a flat tyre
is indicated by the heavy thudding of the train as it passes over the rails. In
the second stage, each coach or wagon is thoroughly examined and all defects,
both exterior and interior, are recorded for rectification. Coaches or wagons
found with defects that can be attended to only in maintenance depots are
marked for handling there. The remaining coaches and wagons are attended to at
the terminal (washing line) or in the yard itself.