The Junior Engineer (C&W) staff must be most careful that liquefied petroleum gas does not get on their skin. The effect is substantially the same as when dry ice comes in contact with the skin viz. freezing.

Ammonia gases are poisonous gases and have a characteristic pungent odour, which gives warning of their presence in the atmosphere before dangerous concentrations are attained.

Whenever tank wagons containing petrol or other inflammable fluids are examined, only specified safety torches (battery torches) should be used for this purpose.

The tank barrel should be filled with water to a minimum height of 150 cm during valve testing.

Master valve and bottom discharge valve should be tested in position under air pressure of 0.35 to 0.56 Kg/cm² (5 to 8 psi).

The ruptured frangible disc indicates that excessive pressures have been built up in the tank wagon and may be the first sign of malfunctioning of the safety valve.

In view of the possibility of pilferage/damage, the pressure gauge should be fitted only when required at the time of filling or discharging, or when the pressure is to be checked enroute.

Stiffening plate to be fitted from outside only.

Lists of approved brands and grades of electrodes are published by RDSO every year and these should be available in all workshops and repair depots for reference and guidance.

After completing weld repairs, DP test and radiography of barrel plate should be performed.

Corners of patches should be rounded to a minimum radius of 25mm.

Removal of all paint, grease, oil, dirt by flame heating and brushing is essential both for proper inspection and to prevent contamination of the welded joint.

The welded seams of the tank barrel should be examined thoroughly by applying soap solution, which will show up the crack or other source of leakage.

The hydraulic test pressure for BTPN wagons is 2.8 Kg/cm².

The testing pressure for tanks used for corrosive liquids (caustic soda tanks) is 4.5 Kg/cm².

The hydraulic test pressure for LPG tank (BTPGL, BTPGLN) is 22.1 Kg/cm².

The hydraulic test pressure for Ammonia tank (BTAL, BTALN) is 33.25 Kg/cm².

The pressure should then be raised to the full test pressure and maintained for a sufficient length of time, but not less than 30 minutes.

The tank barrel and manhole orifice should be completely filled with water at a temperature which must not exceed 38 Deg.C (100 Deg.F) during test.

Measure barrel thickness by D-meter to ensure extent of corrosion.

Freedom from alkalinity can be easily ascertained by litmus test - if red litmus changes to blue, there are still traces of alkalinity.

Caustic soda tanks should be washed free of alkalinity with hot water.

A bottle is lowered, tilted to allow gas to enter, then withdrawn and a lighted match stick brought near. If there is no flame, the tank is free from injurious gas.

Any trace of chlorine in water would have a bleaching effect on coloured litmus paper.

Nessler's test is a very sensitive method to find out if the specimen of water contains any traces of ammonia. The reagent gives a brown colour when mixed with water containing even a minute trace of ammonia.

Any trace of ammonia in water would turn red litmus blue. Ammonia is readily soluble in water.

Insert pipe through man hole and steam interior of barrel for 12 hours.

No person should be allowed to enter the tank barrel for internal examination/repair unless the barrel is free from Toxic or inflammable fumes.

For BTCS tank wagons, the periodicity for POH is 4 years.

For BTPN tank wagons, the periodicity for POH is 6 years.

For tanks for petroleum gas BTPGL, BTPGLN, the periodicity for POH is 4 years.

For tanks for petroleum gas BTAL/BTALN/BTPH, the periodicity for first POH is 4½ years.

The main function of the bottom discharge valve is to control the flow of the contents and also to serve as an additional safety stop in case the master valve fails or breaks.

In eight-wheeler stock, two bottom discharge valves are fitted, one on either side and connected with the master valve through a tee pipe.

Master valve assembly is a gravity discharge valve fitted with a hand wheel in the dome for manual operation.

Vapour extractor cock's function is to extract vapour from the tank while filling.

Compressed air valve is provided on tank wagons from which the contents are unloaded by compressed air. Its main function is to control the rate of discharge by controlling the rate of air admission.

Safety vent consists of a frangible disc which ruptures at specified pressure. It is an additional safety fitting to safeguard against the failure of the relief valve.

Relief valve is a spring loaded valve fitted on the barrel of tanks for corrosive liquids. Its main function is to release built up pressure, if it exceeds the working pressure limit.

The safety valve is provided to prevent building up of excess pressure inside the barrel.

For Tank wagon for phosphoric acid type BTPH, the cylindrical portion uses ASTM A 240 55 316 L.

For Petrol tank wagons type BTPN, the cylindrical portion uses IS:2062 Fe410Cu-WA.

For Ammonia tank wagon type BTALN, BTALNM, the cylindrical portion uses Steel to BS:1501-224 Gr.32 ALT 50 or ASTM-516 Gr-70.

The barrel is placed longitudinally on the underframe and secured by means of rivets/welding to the saddle.

The barrel is cylindrical vessel generally fabricated out of low carbon structural steel to IS:2062 Fe 410CuW.

A pair of saddles is provided on the underframe at each end for mounting the barrel.

Since the population of four-wheeler tank wagons and tank wagons on UIC bogies have been phased out, details of these stocks have not been included in this manual.

For information about these wagons in respect of their mechanical code and the products carried, refer to Appendix "B" of IRCA Part III (Latest edition).

The four categories mentioned are: tanks as pressure vessels, tanks for corrosive liquids, tanks for petrol and highly inflammable products, and tanks for middle distillates of petroleum and others products.

Tank wagons are classified according to the product carried by the tank and its design. They form a special class of non-pooled rolling stock.