Vince's World: Another great day at Urmston - the last for a couple of weeks for me

Wet weather yesterday, but what a great day today!

Superb pictures as always by Jason Lau. Please click on any one for a larger image.

'The Beast' is pushed across the bridge by Keith while I wait on the convenient wall with our 'gear'. Jim is next in the queue, to unload his Beyer Peacock Tank from his car, then I'll back the car in and unload 'Alfred'.

'Alfred' on the 'arrivals table' ready to roll to the prep bays

Pete Flitcroft watches as I traverse 'Alfred' across to the prep bay feeder tracks

First job on the prep bay is to connect tender to loco. There are three water connections; one for each of the two injectors, and one for the tender hand pump. Here I try to make the latter connection, which is proving difficult.

Eventually we get the water pump connector to connect (a circlip was not in its groove - soon sorted once spotted). Our green hose provides us compressed air for the blower (used to blow air up the chimney to get the fire going on lighting up) and for cleaning-down on loco disposal, and water for filling the boiler and tender. The club provides water and compressed air connections on each prep bay.

On the prep bay. We prep as Jim brings his Beyer Peacock Tank to the prep bays.

Jim preps his Beyer Peacock tank, Keith does the same with 'The Beast', while Malc and I prep 'Alfred'

Malc oils round while I shovel paraffin-soaked charcoal (from the plastic Chinese Take Out box on the tender) into the fire box prior to lighting up. Once that is burning well, coal is added. Note the compressed air 'blower' in 'Alfred's' chimney. Just before I put a shovel full of lit charcoal into the firebox to 'light up', this blower is turned on to provide a draft through the firebox, through the boiler tubes, and up the chimney to draw the fire. White smoke (from the paraffin) then issues from the chimney. At this point I have already checked that the tender hand pump, when operated, is delivering water to the boiler

That blower can be clearly seen here, as Malc continues to oil round. As soon as we have about 30psi on the pressure gauge I dispense with the compressed air blower and turn on 'Alfred's' steam blower, which is far more effective. So much so that as boiler pressure rapidly rises I have to keep turning the blower down. But in about fifteen minutes from lighting up 'Alfred' is blowing off.

I deliberately let him blow off to check that the safety valves lift at 90 psi, and the boiler pressure does not exceed that value by more than 10% despite continued use of the blower (i.e. the safety valves can pass enough steam to contain the excess pressure). I also check both injectors at this time; blowing off uses a lot of water and the injectors can be used to restore the level and confirm that they each 'pick up' as they should.

To operate an injector, first the water feed is turned on (water should be seen flowing from the injector overflow), then the steam flow turned on, and, if required, the water flow trimmed back until the injector 'picks up' with a singing gurgling sound and the flow from the overflow ceases. The water is now entering the boiler via the appropriate clack valve (a non-return valve). When the gauge glass confirms that the required water level has been reached, the steam is turned off, followed by the water.

On 'Alfred' the left hand injector does require the water flow to be trimmed back until the injector 'picks up'. The right hand injector is one that delivers a much higher flow; it does not usually require 'trimming back', picking up as soon as the steam flow is turned on. However, both injectors 'pick up' more readily if the water is turned on, then a pause, before the steam is turned on.

Sometimes (injectors are strange beasts) it requires a blast of steam to get the water to flow, then it's 'steam off', let the water flow for a couple of seconds, then steam back on and trim if required for it to 'pick up'.

Also, if the boiler steam pressure is too low, the injector will not pick up. If you have backed yourself into that corner, you will need to resort to the tender hand pump and get pumping to restore boiler water level before it becomes critical; if the firebox crown is exposed it will melt, which will result in... disaster! The boiler pressure is normally 90 psi on 'Alfred' (up to 250 psi on a main line loco), and contains water at about 170 degrees C, which on release of pressure will flash to steam. The energy released in a boiler explosion is phenomenal. Small wonder that a steam locomotive crew's first and over-riding priority is maintaining a safe boiler water level.

A hot injector (one that has had just steam and no water through it) will not pick up until it has cooled. And the feed water must be cold. An injector only works with cold water, not warm, a problem for tank engines (especially saddle tanks) where the water in the tank gets warmed by the adjacent boiler.

It is always satisfying when an injector picks up when you expect it to, and sings to let you know it is delivering water to the boiler.