At this point, most railways decided to abandon snifting valves.

These problems are avoided by using snifting valves to allow air to be drawn into the cylinder.

UK railway companies did not agree on the merits of snifting valves.

The snifting valves may mounted directly on the cylinders or steam chests.

When built all engines had smokebox mounted snifting valves.

A number of modifications were carried out over their life including the fitting of large mushroom air snifting valves.

With somewhat different functions, snifting valves were also used in atmospheric steam engines and hydraulic rams.

Side valves were driven via a gear-driven camshaft, with automatic snifting valve activation.

The probable explanation for this diversity is that snifting valves were useful as long as steam temperatures were relatively low.

The entire U1 class had smokebox snifting valves, a feature previously used on the other Maunsell moguls.

The snifting valve can be seen behind the chimney on many LNER locomotives.

If a superheater is fitted, one or two snifting valves may be mounted on the "wet" side of the superheater header.

On railways which did not use snifting valves, drivers were instructed to keep the regulator slightly open when coasting to avoid the creation of a vacuum.

A snifting valve (sometimes snifter valve) is an automatic anti-vacuum valve used in a steam locomotive when coasting.

However, he had Maunsell's smokebox-mounted anti-vacuum snifting valves removed at the end of the Second World War in an effort to reduce maintenance.

Another solution is to have a mechanism such as a snifting valve that automatically inserts a small bubble of air when the suction pulse mentioned above reaches the pump.

Some locomotives (particularly on the London and North Eastern Railway) were fitted with snifting valves which admitted air to the superheater when the locomotive was coasting (drifting).

The smokebox snifting valves applied to the class by Maunsell were removed by his successor Oliver Bulleid, who also fitted U1 class chimneys to improve the draughting.

Snifting valves were provided to prevent vacuum formation in the cylinders when the locomotive was stationary, and the outside Walschaerts valve gear incorporated single slide-bars and piston tail rods.

Snifting valve (not shown) - An anti-vacuum valve which permits air to be drawn through the superheater and cylinders which allows the engine to coast freely when the regulator is closed.

The smokebox snifting valves were removed by Oliver Bulleid by the end of the Second World War, although the U1 class chimney was used to improve draughting on the other Maunsell moguls.

The first of the production batch emerged from Brighton works in August 1928 and featured a tapered chimney and smokebox snifting valves, both of which were used on the K and N class locomotives.

To prevent this a release valve called a "snifting clack" or snifter valve was added near the bottom of the cylinder.

It has numerous fittings which include compressor silencer, snifter valve, blow down silencer, steam turbo and mechanical lubricator.

A snifting valve (sometimes snifter valve) is an automatic anti-vacuum valve used in a steam locomotive when coasting.