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The New Zealand Railways Magazine, Volume 1, Issue 4 (August 24, 1926)

The Westinghouse Air Brake — Recommended Practice

page 36

The Westinghouse Air Brake
Recommended Practice

1. All new Westinghouse Brake gear must be examined, cleaned, oiled and tested before being sent into service.

2. All air brake combined sets, brake cylinders and reservoirs, when bolted to plates or iron faces, should have a strip of tarred roofing felt between the two iron faces. This not only prevents them from rusting but it also enables the faces to bed well together.

3. All brake pipe joints and connections should be placed where they may be conveniently and easily reached. This will simplify repairs and replacements.

4. All train pipes should be kept as straight as possible. Where bends are necessary they should be kept easy and free. Elbows should never be used in brake pipes, as they restrict and retard the flow of the compressed air.

Scene on the Wanganui River

Scene on the Wanganui River

5. All union and pipe connections should come easily together and true. No force should ever be used to bring the faces or ends together. If the pipes or joints are strained when they are being connected, it will probably cause the joints to break, or to become slack, and cause the air brake to become defective.

6. Always clamp and secure the train pipes well to the vehicles so that they will not shake. A slack train pipe, if not attended to promptly, will likely cause leaks and other air brake troubles.

7. When making air pipe joints use only tallow and flax. Red lead and similar substances must not be used on air brake pipe fittings.

8. All brake pipe threads should be of full size and true, and every case should fit well into the connections without shake or looseness. Worn or loose pipe threads never give satisfactory air brake service.

9. All standard steam bends used for air brake purposes should have the sand scraped out, and be blown out with steam before being used.

10. All air brake pipes when completed, and before being placed on the engines or vehicles, should be blown out with steam.

11. Only the best heavy steam pipe and steam pipe fittings should be used for air brake work.

12. When overhauling the air brake on engines, tenders, or vehicles, the triple valves should be cleaned, oiled, and tested at the bench.

13. The standard triple-valve piston ring test is carried out with the triple piston off its seat, and the triple slide valve on lap. With a continuous pressure of 75lbs, the compressed air must pass the triple piston ring into an empty auxilary reservoir of 1,458 cubic inches capacity (10 in. by 24 in.) at a speed of not more than 30 lbs. per minute. With new triple valves and with 75lbs. continuous pressure the compressed air must pass the piston ring into the reservoir at a speed not greater than 15lbs. per minute. Should these pressures be exceeded the triple valve piston rings must be put in order.

14. Great care is required when triple valve piston rings are being fitted. These piston rings should fit closely around the whole part of the bush, and the end joints should fit closely together. Triple valve piston rings should be ground in with oil only. No emery or other abrasive material should ever be used.

15. When the triple slide valve or its face needs refacing, they should be scraped to a page 37 perfect face and afterwards worked together with a little oil. No emery or other abrasive should ever be used when fitting triple valve piston rings, or slide valves.

16. When renewing air brake leather gaskets, rub a little tallow on the faces of the new gaskets or leathers.

17. Air brake leathers or gaskets should never be placed in hot water, or cleaned with kerosene, as this takes out the wax filling and causes the leathers to leak.

18. Great care should be taken when placing brake cylinder pistons and piston leathers into the brake cylinders. First place the piston into the cylinder at an acute angle and work gradually until it is in the central and correct position.

Air Pumps.

19. The tophead main valve piston rings should be a good fit (without being too tight) in the cylinders or bushes. These rings should fit the piston head grooves closely and without shake. The piston ring ends should fit closely together.

20. When air pumps are being overhauled, the steam and air cylinders should be callipered, to see if these cylinders are parallel, before the piston rings are fitted.

21. The steam and air cylinders should be rebored when the ends are 1–16th in. larger than the centre of the bore.

22. Air cylinder piston heads should be replaced when the diameter is 1–16th in. less than the bore of the cylinder.

23. The fit of the air piston head on the rod should be a light driving fit when the end of the rod is parallel, but when the piston rod end is tapered there should be 1–32 in. draw.

24. Piston packing rings for air or steam cylinders should be condemned when the openings are 3–32 in. apart when placed in the end of the cylinder.

25. Piston rods should be trued up when cut or worn 1–32 in.

26. All screws and threads should be coated with graphite lubricant before being fitted together.

27. Steel air valves are preferable for all air pumps.

28. Worn nuts should never be placed on the air piston rod end.

29. The air end of the piston rod should be annealed each time the air pump is overhauled.

30. The lift of the air valves should be minimum 3–32 in., maximum 5–32 in.

31. It is important that the steam and air cylinders of the air pump be properly and regularly lubricated with suitable oil or grease.

32. Oil the steam cylinders with good cylinder oil and the air cylinder with paragon grease.

33. Tallow or animal or vegetable oils must not be used to lubricate the air cylinder.

Main Reservoirs.

34. Main reservoirs should be of the tube design. These should always be located on the engine and be securely and firmly attached with proper supports, to the underside of the running board or on some other suitable part of the engine.

35. Wood packing, or wood supports on the main reservoirs do not give satisfactory results, as owing to shrinkage, the wood blocks become slack.

36. Main reservoirs for freight engines should not be of less than 40,000 cubic inches capacity.

37. For passenger engines the main reservoir should not be of less than 30,000 cubic inches capacity.

38. Only two connections, the inlet and the outlet, should be made to the main reservoir, and these openings should be separated as far as possible. The discharge opening should be near the top part of the main reservoir so that the water or moisture will not pass into the brake pipes.

39. All air brake main reservoirs should be fitted with drain cocks.

Air Gauges.

40. Air brake pressure gauges should be placed conveniently, and in clear view of the enginedriver. The duplex pressure gauge should be well lighted, and so placed that it can be seen clearly by day and by night. Air gauges should be tested at regular intervals.

41. Particular care should be exercised when placing the driver's brake valve. This should be well within the reach of the enginedriver when he is looking forward, and when he is looking back out of the cab window from his usual position in the cab.

(To be continued.)

Some Slogans.

Caution brings safety.
Safety all ways, always.
Better careful than crippled.
Better safe than sorry.
Safety spells success.
Care stops trouble.
Darkness spells danger.
An ounce of help is worth a ton of pity.
Your eyes your guard.
Save yourself you save others.