Off-Track Tampers
Off-track tampers are portable and can be quickly taken off
the track by just two people. These tampers work during the interval between
the passage of trains and do not require any traffic blockage (Fig. 20.1). They
consist of tools driven by compressed air, electricity, or petrol. There are
generally two types of tampers, namely, self-contained tampers and those that
are worked from a common power unit. Tampers may be vibratory or of the
percussion type or a combination of both. In the vibratory type, tamping is
achieved by vibration as well as by the weight of the tamper itself, while in
the percussion type. tamping is achieved by imparting blows. The important
off-track tampers tried on Indian Railways are Cobra tampers, Jackson tampers,
Shibaura tampers, and Kango tampers.
1 Use of Off-track Tampers
Off-track tampers are placed
diagonally under the rail and worked in pairs from the opposite sides of the
sleepers in order to ascertain the maximum consolidation of the ballast. Using
beaters, the ballast is first loosened around the rail seat in the crib for a
length of 450 mm (18") on either side of the foot of the raft. The tamper
is then inserted vertically and the tamping tool blades are kept about 75 to
100 mm away from the sleeper so that enough ballast is available between the
two as shown in Fig. 20.1. During its working, the head of the tamper should be
moved slightly backward in the shape of an arc of a circle so that the
surrounding ballast is well compacted. The operator should not exert force on
the tamper while tamping is being done using either the vibratory system or the
percussion system.
The average progress achieved by
one set of off-track tampers is about 3 km per month, after taking the repairs,
overhauling , etc. into consideration.
2 Limitations of Off-track Tampers
Off-track tampers have not been
much of a success on Indian Railways because of the following reasons.
(a) The
maintenance of these tampers has been found to be extremely difficult because
of the non-availability of spare parts, which are mostly imported.
(b) Transporting
off-track tampers along with their power units to the site of work in the
mid-section is quite problematic.
(c) Tamping
with off-track tampers is very strenuous and a worker normally gets fatigued
after 30-40 minutes. The quality of work done after this duration is likely to
deteriorate.
(d) Intensive
supervision is required to ensure the correct use of these tampers so that the
work done is of the desired quality. This type of supervision becomes
particularly difficult in the mid-section.
(e) The
quality of tracks maintained using tampers is not very high compared to those
maintained by manual methods.
(f) The use
of off-track tampers following deep screening and relaying work has been found
to be very unsuitable for the early restoration of normal
speed.
However, off-track tampers are
yet to be tried under the following conditions on Indian Railways.
(a) For
packing the points and crossings where normal packing cannot be done
effectively due to limited space.
(b) For packing newly realigned curves, on which the track requires immediate consolidation so that its alignment remains undisturbed and normal speed can be restored along its length as early as possible.
Related Topics
Privacy Policy, Terms and Conditions, DMCA Policy and Compliant
Copyright © 2018-2023 BrainKart.com; All Rights Reserved. Developed by Therithal info, Chennai.