GRAVITY GOODS ROPEWAY
Rural economy in Nepal is largely based on
subsistence agriculture. Without allocation of
resources by the central government, infrastructure
development at the local level is almost impossible.
Due to this fact, the rural communities from ages
are facing rather exhausting, time consuming
and often dangerous journeys to access basic
services like administrative, health and education
facilities, and access to markets to sell their
produces. Each year substantial quantities of
surplus agricultural produces perish due to lack of
adequate infrastructures and facilities to transport
them to the markets in time. As such, rural
communities survive with subsistence agriculture
despite the huge economic and market potentials.
Gravity ropeway facilitates the transport of local
produces to the road heads and market centres,
thus encouraging the communities to engage in
commercial farming.
As the travel time is less than two minutes to bring
down the goods from village to markets downhill,
perishable goods can be transported to the
markets in no time which considerably prevents
them from getting rotten. Gravity ropeway can be
an economical solution to transport goods to the
hills and valleys and vice-versa. Export of greater
quantity of local produces from the village and
import of lesser quantity of outside materials to
the village will be an ideal condition to install a
gravity ropeway which will ultimately promote local
produces and help boost the local economy.
Gravity goods ropeway is not an alternative to
road transportation but it rather add values to
the existing road network by complementing it in
goods transportation from the remote locations
to the road head. Therefore, gravity ropeways
should be an integral part of the District Transport
Master Plan (DTMP) for the mountainous and
hilly districts.
1.3 Ropeway Mechanics
The mechanics of the gravity ropeway works on
a very simple pulley system. It consists of two
trolleys, rolling over two separate steel wire ropes
(track ropes) supported and suspended over two
separate towers at the top and bottom ends.
The two trolleys that slide on the track rope are
connected to a single looped wire rope (hauling
rope) of a smaller diameter by means of rope
ties. This hauling rope passes around a cast iron
sheave at the top and bottom stations. When the
loaded trolley rolls down by its own weight along
one track rope from the upper station, another
trolley with lighter weight at the bottom station
hauls up along the next track rope as they are
connected to the haulage rope. A simple brake
with a rubber/wooden brake shoe is fitted to the
sheave at the lower station to regulate the speed
of the moving trolleys.
As a rule of thumb, the weight ratio of downward
to upward moving load is 3:1. However, the ratio
varies according to the slope of the site and
precision maintained during installation of gravity
ropeway. Hence, the proper loading ratio per site
should be carefully evaluated after the gravity
ropeway comes into operation and should always
be maintained within the ratio prescribed.
Theoretically, the velocity of trolleys at each
point along the route corresponding to the given
loading ratio can be obtained from the following
equations or relations.
Let us suppose m1 be the mass of downward
moving trolley with load and m2 be mass of
upward moving trolley with load. Here, m1 is
always greater than m2.
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