Shell Chapter 2

CHAPTER 2 SHELL 201 DESCRIPTION form part of the tubular construction as well as to absorb a large portion of the buffing forces. Anti-t elescopic structure has been provided in the end -walls to avoid telescoping of the adjacent coaches and to absorb the major part of collision energy in case the ends collide during heavy collisions. The concept of the lightweight integral design originated in the recognition of the properties of hollow girders from the point of view of strength and utilization of material. The reduction in tare weight of these coaches could be achieved by utilising "stressed skin" concept and by use of low alloy fittings. Corrugated sheets are utilised for the trough floor to Leading dimensions of ICF, BEML and IRS are (see figure 2.1): Table 2.1 Over Buffers (mm) Over Body (mm) Over all width (mm) ICF/RCF BEML IRS 22297 22296 21996 21337 21336 21030 3245 3250 3251 Height from Rail level (mm) 4025 3991 3886 HEIGHT FROM RAIL LEVEL Coaches OVER BODY OVERALL WIDTH OVER BUFFERS COACH SHELL Figure 2.1 201a The integral shell is made of a framework of series of hoops, consisting of floor crossbeams, body side pillars and roof carlines located transversely at regular intervals, to suit door and window openings (see figure 2.2). These hoops are connected together by sole bars, waist rails, light rails, cant rails and carlines longitudinally. This frame work is sheathed all over by 2 mm thick corten steel (IRS-M -41) on the side walls and 1.6 mm thick corten steel on the roof. At the bottom 2-mm thick corten steel corrugated trough floor is provided between the sole-bars and running over the length between the head stocks of underframe. The whole forms a tubular shell of integral construction in which the sides and roof panels also share the load. The corrugated trough floor with its corrugations running longitudinally from one head stock to the other takes up the buffing loads. Below lavatory the tubular constructions are provided in place of trough floor to avoid corrosion due to seepage of water (See figure 2.2). In coaches with stainless steel trough floor, no tubular structure is used. CAR LINE CANT RAIL BODY PILLAR LIGHT RAIL WAIST RAIL SOLE BAR SIDE WALLSHEET THROUGH FLOOR SHELL FOR ICF COACHES (CROSS SECTIONAL VIEW) Figure 2.2 201b End wall consists of four vertical pillars of box section connected transversely by `Z' sections and are welded to the head stock at the bottom and to the roof at the top. (See figure 2.3) 201c The head stock of BG integral coaches consists of outer and inner head stocks connected by two rigid center buffer stiffeners, which transmits all the buffing forces to the under frame structure. 201d Under -frame acts as support for mounting equipment like air or vacuum brake system (brake cylinders, DV, BP & FP pipes, auxiliary reservoirs, control reservoirs, etc.), air -conditioning system (Compressor unit, Battery, Control rectifier, etc.), train lighting battery boxes, under slung water tank, etc. 202 BODY REPAIRS 202a Inspection and repair of body members are done after the coach body is lifted off the bogies and placed on trestles. 202b All furnishing and other components from coach shell, which are stripped, are to be sent to the respective sections for maintenance. See figure 1.1 (In chapter ‘Coach’) for normal repair chart for sequential POH repairs and fitment of overhauled equipment 202c Inspection of Underframe i) The underframe members should be thoroughly inspected for locating cracked/bent/corroded members. Corrosion is indicated by flaking of paint, flaking of metal, pitting and scale formation. Components like sole bar and trough floor which are not visible from both sides should be examined by tapping with a spiked hammer. Proper illumination will be required to carryout the check. A component will require repair/ replacement, if it has lost more than 20% of it’s thickness . 25 5.0 2.0 110 252.5 110 25 END STANCHION 406 406 406 3107 406 STIFFENER 283 110 482 110 635 635 110 3240 END CONSTRUCTION OF BROAD GAUGE ALL METAL LIGHT WEIGHT COACH ICF Figure 2.3 482 110 283 sufficient length and all the exposed parts, after scraping and cleaning, should be examined to determine the extent of corrosion. ii) Particular attention should be paid to the more vulnerable members and locations listed below:§ § § § § § 202d Sole bar, body pillars, turn under and tubular frame/ trough floor below lavatories in all types of coaches and the luggage compartments of all SLRs and parcel vans. Sole bars, body pillars, turn unders and pillars above lifting pads Sole bars and pillars behind the sliding door pockets of SLRs and parcel vans. Sole bars, pillars and turn unders at the door corners. Head stock. Sole bars, pillars and turn under near coach body bolster. Procedure for inspection of underframe members for corrosion attention in case of vulnerable and not so -vulnerable locations should be followed as given in RDSO technical pamphlet No. 7602 (Rev.1) i) ii) Sole bar, turn under and pillars above the lifting pads § Examine the above members in the same manner as described para 202d (i ) § If signs of corrosion are noticed, the side wall sheet above the lifting pads should be cut to a height of 500 mm. above the turn under and to a length of half metre, on either side of lifting pads. Scrape the structural members, clean and examine minutely to ascertain the extent of corrosion. iii) Sole bar and pillars at door corners § Sole bar, body pillar and turn under at lavatory area § § § Examine visually supplemented by tapping with a spiked hammer sole bars, body pillars and turn under in the bays under and adjoining lavatories from below the coach and through the elongated holes in the turn under after removing the accumulated dirt and cleaning the surface through the holes. If corrosion is suspected at places in the coaches without elongated holes in the turn under, a 100 mm diameter hole should be cut in the bottom of the turn under without damaging the pillars for examining the inside. If incidence of corrosion is noticed in the bottom half of the sole bar, the trough floor should be cut to a width of 300 mm and requisite length for examination of inside top half. If heavy corrosion is noticed, the side wall should be cut to a height of 500 mm. from the bottom of turn under covering iv) Examine the above locations visually. If corrosion is noticed, cut the turn under to a width of half metre from the door corner. Remove accumulated dust. Structural members should be thoroughly scraped, cleaned and examined to assess the extent of corrosion. Sole bar, turn under and body pillars at locations other than those described above § Examine visible portion of sole bar through the elongated holes of turn under and from bottom of the underframe. § Remove the accumulated dust in the turn under through elongated holes and scrape structural members to the extent possible. If corrosion is noticed, side wall sheet in the area of corrosion should be cut to a height of 450 mm. from the bottom of turn under covering sufficient length for thorough examination.