Early May overhaul news – Darlington

Tornado’s atomisers are in the process of been overhauled at Darlington Locomotive Works (DLW). This is a very small and fiddly but necessary time-consuming job.  The atomisers are part of the locomotive’s cylinder lubrication system, and to ensure their efficient and reliable operation are been stripped right down for examination and where necessary repair.  Photos by Richard Pearson.

Here you can see the component parts of one of the Non-Return Valve (NRV) – oil is delivered from the mechanical lubricator via the NRV, and in normal operation the NRV stops steam (at boiler pressure) from passing back up the pipework and into the lubricator. Work on the NRV’s includes a thorough clean and de-carbon, the tapered plug valves have all been lapped in with fine grinding paste, and the coil springs have all been replaced with new springs.

Once the oil has passed through the NRVs it enters a chamber where is mixes with steam, the image above shows the mixing chamber inserts, the insert on the right has already been cleaned the other two are still to be cleaned, all three are in good condition and once cleaned will be re-used.

The fully assembled and overhaul left-hand atomiser.

The slow and heavy job of stripping down and overhauling the rocking fire bars is also taking place at DLW.  The firebox has twelve rocking firebars, six on each side, and on average we are overhaul about one and a half rocking bars per working day.  The bars are dismantled, and the individual finger bars removed for examination, most finger bars require the attention of angle grinder to dress the edges but some do require full replacement if hairline cracks are found, the main rocking bar and the clamping plates which hold the fingers onto the bars are then set up against a straight edge and where necessary put in the hydraulic presser for straightening, after which the bars are fully assembled.  The picture shows volunteer George Bee assembling one of the rocking firebars.

The boiler cladding is back at DLW for repairs and painting, as the picture shows, with Ian Matthews sanding the dome cover.

The smokebox door has an inner lid which has been cut off to gain access to the inside.  It was full of ash!  Ian Matthews is seen  grinding the dart hole in order to create a tight fit so that ash can’t get in again.  Once done the lid will be welded back on.