ICF COACH SHELL / BODY
Construction of coach body which forms big tubular hollow construction which is light in weight.
Salient Features of ICF Coach Shell / Body
All Metal: - ICF coach shell is made up of steel channel frames of thin sections except the seats & luggage racks which are made up of wooden members.
Light Weight:-The weight of coach shell is reduced due to minimal use of wooden members, use of anti-corrosive Corten Steel (IRSM 41) of thickness 1.6 mm for roof and 2 mm thickness for corrugated floor, side panel and end panels during fabrication of coach body. The use of gusset plate, knee & rivets are also avoided in under frame. Hence weight of ICF shell is reduced by 26% to 32% compared to IRS coach shell which was used in the past.
Integral Construction:-The shell of ICF coach is formed by welding together body side pillars, roof carlines, waist rail, light rail, cant rail & sole bar. Corrugated flooring, side panels, end panels & roof are welded together by means of homogenous welding. End pillars, stanchions and side pillars are also connected with panelling work. This type of structure gives the integral
Anti-telescopic construction:-The shell of ICF Coach is designed to bear 45 tons of vertical load and 200 tons of longitudinal impact on side buffers. The coach body is so designed that it is stronger at end portion as well as in passenger seating portion and less at the doorway and toilet. Due to which maximum kinetic energy during accident is absorbed by the end portion and get damaged and balance kinetic energy is also shared by the corrugated flooring and other members of body shell, resulting in keeping the passenger accommodation area of middle portion of shell safe with minimum damage. As a result of these properties, 6 telescoping of one coach into adjacent coach is avoided during accident. Hence the above type of shell construction is known as anti-telescopic construction.
Stressed Skin Construction: - During the construction the side panel is welded to side pillars, waist rail, light rail and cant rail by means of CO2 welding which results in accumulation of stress in the panel. The stress is relieved by spot welding on the panels at different location after completion of the construction. 70 % of total developed stresses are absorbed by corrugated trough flooring. Thus this multi-point welding property of the end & side panel is enough to minimize developed stresses of panels.
Aerodynamic shell: - The shell is constructed with the curved roof at the corners and curved turn under to minimize the air resistance during the run of the coach at high speeds.
Anti-corrosive:- To achieve anti-corrosive property to the shell, Corten steel IRSM - 41 (max at turn under and lavatory portions) is being utilized for panelling purpose. During manufacturing the process of sand blasting, grit blasting is also given on panel sheet which is helpful to prepare rough surface for painting resulting in less chances of corrosion. Three coats of bituminous anti-corrosive paints are given at welded portion and for other portion red- oxides paint is applied for anti-corrosive treatment. The Trough floor is provided with holes for proper drainage of water. 200 x 135 mm size elliptical holes are given in turn under portion for proper drainage of seeped water coming from window shell. The flooring inside is made of 19 mm thick ply or 12 mm thick COMPREG sheet and 2 mm PVC flooring is layed over it avoiding the seepage of water from the floor below to the 7 corrugated sheets. The above precautions and provision of facilities minimizes the incidence of corrosion.
Heat resistance: - To improve thermal insulation property in coach shell following precaution or facilities has been provided:-
Silver / Aluminium paint coat is provided on roof outside which reflects the sun rays.
Further the ceiling is provided with layers of insulating materials like Asbestos / Glass wool which is bad conductor of heat resulting in minimum transmission of heat to interior of the coach. The carlines are designed with elliptical holes for proper air circulation from one compartment to another. Sufficient no of ventilators are also provided on top of roof for exhausting the stale and hot air from the coach and to circulate fresh air. Limpet sheet is used for inside ceiling (2mm thick) which is bad conductor of heat.
