Total direct activities for POH of AC LHB coaches is 21 days, with various parallel activities running simultaneously to optimize workshop time.

DRS reports are prepared jointly by Engineer (C&W)/Engineer (Electrical) with RPF representatives to document deficiencies in coaches before departure.

Fire extinguishers should be checked every three months and completely refilled after one year. They should not be overdue testing/refilling.

In AC coaches, floor is cleaned with vacuum cleaner, while sleeper coaches are swept with broom.

Indian style lavatory pans have to be cleaned by thorough rubbing with concentrated solution of recommended cleaning agent.

Coach cleaning/washing should be done by 'Automatic Coach Washing Plant (ACWP)'. Where not available, manual method with proper precautions is used.

Primary end requirements include 100% brake power through proper adjustment, zero missing fittings, intensive toilet cleaning, and 6 hours clear pit time.

During rolling in/out examination, the speed of the train shall not be more than 30 KMPH.

D3 Schedule includes all D1/D2 activities plus examination of trough floor and underframe from underneath for corrosion.

D1 Schedule includes visual check of destination boards, body panels, end walls, windows, doors, head stock, sole bar, and underframe members.

Preheat the crack location to about 150°C by oxy-acetylene flame and ensure temperature by using thermal chalk.

Welders deputed to carry out welding work on coaches and coach components should be only those tested and certified as adequately skilled for welding work on coaches.

NO electric welding on coach without proper earthing from near the portion being welded. Return current through bogies and rails passes through axle roller bearings causing pitting and bearing failure.

All coaches after Shop Schedule should be tested under water spray for roof leakage before they are finally turned out from the workshop.

For minor corrosion, paint and rust should be thoroughly cleaned to bare metal, then treated with two coats of red oxide zinc chromate primer followed by four coats of anti-corrosive bituminous paint.

Vulnerable locations include sole bar, pillars, trough floor below lavatories, luggage compartments of SLRs, areas above lifting pads, and door corners.

Corrosion is indicated by flaking of paint, flaking of metal, pitting, and scale formation.

A component will require repair or replacement if it has lost more than 20% of its thickness due to corrosion.

Coupler height shall be adjusted by adding or removing shims from the bottom of the coupler carrier assembly when the vehicle is empty and at rest on a level track.

For production units, maximum height of CBC under tare condition is 1105 mm and minimum is 1095 mm.

Lines should be protected by scotch blocks with locking arrangement and keys should be kept with Engineer till maintenance work is completed.

Coach must be lifted from designated lifting pads only, never from any other point, and never from one end only.

SS-I is due at 18 months + 30 days OR 6 Lakh km earned, whichever is earlier.

D3 (Six Monthly) Schedule has periodicity of 180 days ± 15 days.

D1 (Trip) Schedule is to be carried out every trip or weekly, whichever is applicable.

As per Railway Board letter RBA No 25/2006 dated 25.05.2006, full Stainless Steel body coaches have a service life of 30 years, while steel body coaches have 25 years.

Main components of underframe include head stock, body bolster, sole bars, and cross members.

Roof sheets are manufactured from 1.25 mm and 1.7 mm Austenitic stainless steel, making them significantly lighter than ICF coaches.

The gap between two end walls is only 300 mm, reducing wind resistance and turbulence at high speeds.

Side wall thickness has been reduced from 90mm in conventional designs to 60mm, creating additional interior space while maintaining structural integrity.

Side wall sheets have a uniform thickness of 2 mm, providing optimal strength-to-weight ratio.

Side walls are manufactured using TIG Welding for low heat inputs, less distortion, and negligible shrinkage during fabrication.

The cumulative effect of various insulation measures limits the noise level inside the coach to 60 DB, ensuring passenger comfort even at high speeds.

Heat insulation includes 60mm Glass Wool for roof, side walls, and end walls, while 30mm Glass Wool is used for flooring.

PU-based spray insulation on interior surfaces serves the dual purpose of corrosion protection and sound damping.

IRS M-41 Corten Steel has carbon maximum of 0.01%, along with other alloying elements like Chromium, Nickel, and Copper.

Underframe is fabricated from IRS M-41 Corten Steel with specific composition including C 0.01% max, Cr 0.35-0.6%, Ni 0.2-0.47%, Cu 0.3-0.6%.

Roof sheet and trough floor are made of Austenitic stainless steel with ultimate tensile strength of 550-750 N/mm² and yield stress of 235 N/mm².

Ferritic stainless steel (X2CrNi12) is used for side walls, end walls, and roof structure with UTS 450-600 N/mm² and yield stress 320 N/mm².

LHB Coach features integral light weight construction consisting of separate assembly groups for underframe, side walls, roof, and end walls joined by welding, creating a monocoque structure.