FIELD OF INVENTION
The present invention relates to manufacture of light weight body shell for 4-
wheeler diesel electric tower car adaptable to Indian railway track maintenance.
BACKGROUND OF THE INVENTION
Indian Railway, one of the world largest rail networks with track length of
approximately 63,221 km and for proper maintenance of overhead catenary's
wire a lot of overhead equipments are necessary. For maintenance of these
overhead equipments and catenary wire, Indian Railway needs a self-propelled
vehicle with a small workshop including a lift platform set up.
For this Indian Railway has developed the following vehicles:-
(i) 4-Wheeler Diesel Hydraulic Driven Tower Car with manual driven lift
platform
(ii) 8-Wheeler Diesel Electric Tower Car with hydraulic driven lift platform
Following were the shortcomings of these vehicle:-
(1) 4-Wheeler Diesel Hydraulic Tower Car is having leakage and maintenance
problem. Moreover, it is having manual driven lift platform and low pay load
capacity.
(2) 8-Wheeler Diesel Electric Tower Car is too costly and bigger vehicle to fulfill

requirement of Indian Railway.
In view of above, Indian Railway was trying to replace such equipment by a car
with diesel electric drive, hydraulic driven lift platform with its own power pack
along with small workshop and payload carrying capacity of 10 tonnes. Other
salient features of this vehicle were:-
(i) Track gauge: 1676 mm
(ii) Length of vehicle over buffer: 8540 mm
(iii) Tare load: 22 tonnes
(iv) Payload: 10 tonnes
(v) Loaded weight of vehicle: 32 tonnes
To meet the railways demand, a vehicle with under slung mounted propulsion
equipment and self powered lift platform at the top under restricted weight, a
light body shell structure design with sufficient capacity to meet load carrying
capacity was envisaged.
At present, Indian Railway is using the following vehicles for purpose of
maintenance of overhead equipments and catenary wire of Indian Railway
network:
(i) 4-Wheeler Diesel Hydraulic Driven Tower Car with manual driven lift
platform

(ii) 8-Wheeler Diesel Electric Tower Car with hydraulic driven lift platform
Major shortcomings of 4-Wheeler Diesel Hydraulic Tower Car is that, it is having
heavy body shell structure because of which pay load carrying capacity of the
vehicle was only 5 tonnes. Moreover, it is having manual driven lift platform.
To overcome above shortcomings, a self-propelled vehicle 4- wheeler tower car
with diesel electric transmission including a lift platform with its separate power
pack and payload carrying capacity of 10 tonnes is required to be developed. To
accommodate this power pack and other accessories of lift platform and to
increase payload carrying capacity, a vehicle made of light weight body shell and
capable of meeting required load is proposed to be designed and developed.
OBJECTS OF THE INVENTION
It is therefore, an object of the present invention to propose manufacture of light
weight body shell for 4-wheeler diesel electric tower car adaptable to Indian
railway track maintenance which eliminates the disadvantages of existing state of
art.
Another object of the present invention is to propose manufacture of light weight
body shell for 4-wheeler diesel electric tower car adaptable to Indian railway

track maintenance which accommodates a hydraulic driven lift platform with its
own power pack.
A further object of the present invention is to propose manufacture of light
weight body shell for 4-wheeler diesel electric tower car adaptable to Indian
railway track maintenance which uses same underframe.
A further object of the present invention is to propose manufacture of light
weight body shell for 4-wheeler diesel electric tower car adaptable to Indian
railway track maintenance which accommodates a small workshop for carrying
tools and tackles inside the vehicle.
A still further object of the present invention is to propose manufacture of light
weight body shell for 4-wheeler diesel electric tower car adaptable to Indian
railway track maintenance which accommodates the weight of under frame,
superstructure and carrying equipment within the limit of tare weight of vehicle.
An yet further object of the present invention is to propose manufacture of light
weight body shell for 4-wheeler diesel electric tower car adaptable to Indian
railway track maintenance which is eco-friendly.

BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWINGS
Fig.l- shows body shell assembly comprising of underframe and super structure
Fig.2- shows the photo view of vehicle
DETAILED DESCRIPTION OF A PREFERRED EMBODIMENT OF THE
INVENTION
For manufacturing of light weight shell assembly of the 4-wheeler diesel electric
tower car (DETC) a monocoque concept body shell assembly was used and
material used for manufacturing was steel to IRS M-41. Underframe of the DETC
was made using the formed sections of IRS M-41 corten steel thickness varying
from 4 mm to 25 mm and superstructure was made with corten steel sheets
thickness varying from 2 mm to 3.15 mm. To achieve more strength the
underframe and superstructure are welded, this type of design is termed as
monocoque design. With the help of monocoque design the loads coming on the
underframe are also transferred to superstructure, thus, sharing the load. This
helps in optimizing the weight of the under frame. The welded superstructure
and the under frame together are termed as the shell assembly. Principally,
under frame (008) comprises of longitudinal load carrying beam and these
longitudinal beams are interconnected by transverse 'Z' section beam and at both
ends, buffer plate is provided. Further superstructure comprises of (002) drivers

cab, 2 sidewall and roof assembly. The light weight underframe weighs 2590 kg
and the superstructure weighs 2687 kg.
The newly invented design has got space and load carrying capacity to
accommodate the extra power pack for the lifting platform, which is hydraulically
operated. Summing up all the load carrying capacity has been approximately
increased by around 5 tons. To accommodate the equipments in small length of
vehicle the main propulsion power pack and also the power pack of hydraulically
lifting platform are mounted under slung. The total weight of the equipments is
around 16723 kg.
The design of the shell assembly was optimized using FEM package (ANSYS).
Thereafter the design was validated by doing actual squeeze load testing and
measuring the stresses at different location using the strain gauges in case it
meets an accident. The FEM analysis was done in following three load
conditions:
a) Vertical load of 4 tons/meter running uniformly distributed and point load
due to various equipment provided in the vehicle.
b) Horizontal squeeze load of 100 tonnes applied on buffers.
c) Combination of load specified in (a) and (b).

The design of above shell assembly has been validated by carrying out squeeze
load test combined with vertical loading i.e. load combination 'c' as indicated
above. The shell assembly has passed during above testing.

KEY FEATURE


WE CLAIM
1. A four-wheeler diesel Electric Tower Car (DETC) with light weight body
shell comprising:
- a rectangular shaped superstructure shell having two driver cabins at both
end, two side walls and a roof assembly disposed on an underframe
(008);
- a store room (003) for storing maintenance materials;
- a tank room (004) for carrying water;
- a boom cab (005) for carrying hydraulic equipments;
- a workshop cab (006) for maintenance work ; and
- a corridor assembly (007) at the middle of the car
Characterized in that a power pack hydraulically operated lifting platform is
mounted on the said car along with the said store room for repairing over
head wire line.
2. A process of manufacturing a four-wheeler diesel Electric Tower Car
having light weight body shell comprising the steps of:
- fabricating formed section of IRS - 41 corten steel having thickness 4 mm
to 25 mm to form a underframe;
- chamfering the border line of underframe (008);

- welding the corten steel sheet IRS - 41 having thickness 2 mm to 3.15
mm along the boundary line of underframe to form a rectangular box
shaped superstructure shell;
- welding a roof with same steel sheets;
- making a driver cab at both ends of superstructure (001);
- making a corridor (007) at the middle;
- making a store room (003) for storing maintenance article;
- mounting a power pack with hydraulically operated lifting platform; and
- making a tank room (004) and a boom cab (005) inside the car.

A four-wheeler diesel Electric Tower Car (DETC) with light weight body
shell comprising:
- a rectangular shaped superstructure shell having two driver cabins at both
end, two side walls and a roof assembly disposed on an underframe
(008);
- a store room (003) for storing maintenance materials;
- a tank room (004) for carrying water;
- a boom cab (005) for carrying hydraulic equipments;
- a workshop cab (006) for maintenance work ; and
- a corridor assembly (007) at the middle of the car
Characterized in that a power pack hydraulically operated lifting platform is
mounted on the said car along with the said store room for repairing over
head wire line.