Back on the big track at Urmston

'Alfred' in action at Urmston

Today is Easter Bank Holiday Monday and trains were running on the Urmston track, as they were yesterday. The weather was terrible yesterday so we chose to attend today, though this morning it didn't seem a lot better, with some rain.

Malc is over the worst of his post-hip replacement mobility problems so he came with me, his first visit for many weeks.

Maybe it was the morning rain, but there were few customers to ride the trains today so there was plenty of spare capacity on the 'big track' with few passenger trains running. After a few circuits of the short track we noted this spare capacity and decided to take Alfred onto the big, main, track around the perimeter of Abbotsfield Park. It's not the first time we've done this but now we have more experience with 'Alfred' (and a correctly working right hand injector!) it was time for another go.

I went first and 'Alfred' performed magnificently. Once underway I could 'notch back' the reverser to just short of mid gear to make best use of steam; this cuts off steam admittance to the cylinders early in the piston's stroke, allowing expansion of the steam to do the rest of the work of pushing the piston down the cylinder rather than wastefully admitting boiler pressure steam for the full stroke. This process is akin to changing up to a higher gear in a motor vehicle.

The new injector, with its instant pick up and fast feed rate of water into the boiler minimises time fiddling to keep the boiler topped up allowing more time to keep on top of the other factors vying for a driver's attention. I found I needed to use it twice, and also to fire the locomotive twice, on a circuit of the park. Rapid shoveling during firing reduces the time the fire hole door is open (opening it allows cold air to be drawn through the boiler tubes, killing boiler pressure). Judicious use of the blower during use of the injector was necessary, to compensate for the pressure drop induced by the double whammy of loss of steam and influx of cold water into the boiler use of an injector brings. And of course the blower needs to knocked off completely while the fire hole door is open to minimise the inrush of cold air.

The accumulated experience of weeks of practice on the short track, plus the help from the new injector, meant not only did 'Alfred' complete a circuit of the big track with no problems, he climbed the final long gradient to the finish in fine style, running into the station with 3/4 of a glass of water in the gauge glass and blowing off steam through the safety valve!

'The Beast' being prepared at Urmston

While Malc had a go on the big track Keith invited me to drive 'The Beast' round it. This is a much larger locomotive and with so much more reserve in it's big boiler and firebox it is considerably easier to drive than 'Alfred'. In fact as long as it is fired before leaving the station, and the boiler water topped up, all one needs to do is operate the regulator and brake to drive it. No need to plan your firing or boiler top ups, or even notch it back.

I think I prefer the challenges of driving 'Alfred'!

Here;s a video of a 5" gauge Princess Coronation (my favorite prototype loco) 'Duchess of Sutherland' doing a circuit of the big track at Urmston. 'Alfred' does the trip more slowly, obviously, and the most testing parts are the first gradient (long but not as steep as the second) which starts almost as one leaves the station, the first tunnel marking the foot of the bank which continues until the end of the railings either side of the track. The second, steeper gradient is almost at the end, from the second tunnel to just before arriving back in the station. If 'Alfred' has not been carefully nurtured during the circuit, it's this last gradient that will be the show stopper :

Duchess on Urmston's big track




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First Urmston visit for five weeks

A combination of several Sundays as signalman in Consall box, and Mothers' Day, meant I was not able to get to the Urmston & District Model Engineering Society's running track in Abbotsfield Park until today, five weeks since my last visit. But high pressure is still defining our weather and today was lovely - warm, sunny, and virtually no wind.

Soon after the last time I ran 'Alfred' I replaced the troublesome right hand injector, which has never worked properly, with a new one. Knowing I would not be able to attend Urmston for several weeks I had intended to steam 'Alfred' at home on rollers to check if the replacement injector had cured the problem, but the horrid cold weather meant I never got round to doing that. I was particularly interested today, therefore, to see how the new injector performed.

Once I had 'Alfred' blowing off (full boiler pressure) I let the boiler water level drop to about half a glass on the gauge glass as the steam escaped through the safety valve, then tried the left injector, to ensure it still worked (it did).

Time to try the new, right hand one. I turned the water supply for the injector on and immediately saw an improvement - with the old injector the water had merely dribbled out of the injector drain, now it poured out as it always had with the left injector. I turned on the steam supply to the injector and it immediately 'picked up'. I didn't even need to trim back the water supply as is usual with injectors before the 'pick up' - this one just worked! This boded well for hassle-free operation on the track; it can be quite busy on 'Alfred's footplate when running so an injector that reliably 'picks up' without needing to fine tune the water supply is a bonus. It transpires there was never anything wrong with the clack valve after all despite my earlier fears that that was the cause of the trouble rather than the injector itself.

Furthermore, this injector delivers water at a high rate for a small loco like 'Alfred' which adds to the options for the driver for topping up the boiler water level; the slow-feed left injector, the fast-feed right injector, and finally the tender hand pump.

So now 'Alfred' is 100% operational for the first time in my ownership. It is much more relaxing driving him knowing one has two reliable injectors and the hand pump and I had great fun doing so today. One of the club's more experienced drivers (and the youngest) drove him while I had my lunchtime sandwiches, and said he was a delight to drive.

The new right hand injector in place below the footplate (it's the black tube with three brass pipes and a plastic drain pipe attached). Note that on the trolley, 'Alfred' sits on rollers so the wheel tyres rather than the flanges carry his weight. These rollers can also be used when steaming the locomotive where no track is available, as can be seen in the video in the blog entry for 21st October 2015 when I steamed 'Alfred' at home.

The original faulty injector removed from 'Alfred', together with the data sheet that came with the new one. This shows it will deliver 25 fluid ounces (1.25 pints) of feed water per minute into the boiler, which is a lot for a small locomotive such as 'Alfred'. The data sheet shows that the injector has been tested and will 'pick up' at any boiler pressure between 42 psi and 120 psi. Once engaged, it can remain so at boiler pressures down to 23 psi. The old injector is wearing the shiny new brass pipe connectors that came with the new injector but are not required when fitting to an existing pipework system.

'Alfred' tonight back in the garage on his trolley. The tool kit that goes to site with him resides on the bottom shelf , with sundries such as water and pneumatic hoses and latex gloves on the centre shelf. The tender sits on the garage floor! The new injector can be seen under the footplate beneath the cab floor.

The trolley from behind. It's on wheels so can be wheeled out to the car, minimising the distance I have to carry the loco.

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First Kawasaki W800 ride of 2016

My W800 ventured out today for the first time since the salt went down in November. This picture was taken last October, but I had a lovely ride today through the Cheshire Lanes 'the back way' to visit my mum. A fairly short ride, but no doubt longer ones will follow as the year progresses.

Been riding the Honda Innova around locally which is great fun, but it's good to be back in the saddle of a 'big' bike!

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Churnet Valley Railway Volunteers' Day

'Hotspur' early this morning

Early morning at a hazy Consall today. Before services began for our Churnet Valley Railway Volunteers' Day the Polish Tank was out for a play. I haven't switched in the signal box yet (and won't until the first timetabled train arrives) hence the loco running apparently 'wrong road' towards an 'off' signal.

Later the early spring sun burned off most of the haze. And despite a track circuit failure I discovered when I switched on the power in the 'box all went well.

Me filling in the all important train register 

The Polish Tank approaches Consall this afternoon, after the haze had gone

I wait to collect the Froghall - Consall token from the driver..... 

 .....Like this!

Here's a nice video shot at the Volunteer Day. Note the S160 at about 2 minutes into the video passing the Black Lion with caution before opening up to blast off up the valley. This was because I had a track circuit failure in Consall box which prevented me clearing either the down loop starter or down main starter signals so trains were authorised to pass the relevant starter signal at danger (at 10:16 you can see the Polski Tank passing the up main starter at danger) but I'd also asked the driver to visually check point 11 (the electric point at the north end of the loop) as they approached it. 

I asked them to do this as my stepping outside the protection of the signal interlocking in permitting 'pass at danger' also meant the point was unprotected by the relevant starter signal and if I'd screwed up there was no interlocked signalling protection against the train approaching a wrongly-set point and derailing, or wrecking the point, or both. Once the driver sees the point is correctly set, he accelerates away.

Yours truly can be seen collecting the token at Consall at one point in the video as well.

Volunteer Day video

Another superb day in the valley!

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So, farewell then, Keith....

Driving along in my Triumph Spitfire, top down, playing this at top volume on the Motorola 8-track (remember them?). Nearly shook the interior out of the car when the electronic keyboard comes in after the piano intro.

The music of my youth.

Bye bye Keith.

Click here for 'Trilogy'







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Fifty years since the loss of a BOAC Boeing 707 over Mount Fiji, and some thoughts on mountain wave

It is 50 years on 5th March that BOAC lost Boeing 707-436 G-APFE which broke up over Mt. Fuji with the loss of all on board. The aircraft had just taken off from Tokyo and the crew routed VFR off-airways to give the passengers a view of Fuji. They flew into rotor shear downwind of the mountain and the 707 broke up. I remember this well as the day before a CP Air DC8 crashed landing at Tokyo and there was a poignant photo in the papers of FE taxying out at Tokyo past the DC8 wreckage. 18 minutes later that aircraft was also wrecked. 

Ill fated Boeing 707 G-APFE taxys out at Tokyo past the wreckage of a DC8 that crashed on landing the previous night

The mountain wave rotor induced vertical 'G' loads far in excess of design load (probably in the region of minus 8'G'). The wings outboard of the engines detached, as did all 4 engines which continued ahead powered by the fuel in the pylons and were found some distance ahead of the main wreckage. Later in the break-up sequence the forward fuselage, rear fuselage, tail, more wing parts, and control surfaces all separated from the centre section. The upward gust produced enormous induced drag which caused severe deceleration which ruptured the fuel tanks' forward faces. It was enough for the fuel in the centre section tank to slosh forward, break the front of the tank, and carry on until it reached the forward pressure bulkhead, just ahead of the flight deck. Thus the flight deck filled with fuel, drowning the crew (hopefully they were unconscious by then due the 'G' loads).

The centre section and part of the wing goes down, trailing fuel as white vapour

An absolutely horrific accident which shows the power of airflows around mountains. 

A far less serious, but nonetheless scary, personal brush with rotor turbulence

Some years ago flying to Caernarfon in the Chippy we were caught in rotor downwind of Snowdon. I was not expecting it because the surface wind at Caernarfon, a few miles away, was less than five knots (in the Fuji accident the summit winds were in excess of 70 knots on the accident day). I have never know turbulence like it - it was impossible to control the aeroplane; it was in the hands of the elements, being thrown violently up, down, and rolled in spite of any control inputs I made (not many as my backside was, despite a tightened full aerobatic harness, not in contact with the seat most of the time). I remember wisps of cloud forming and dispersing around us. Then it spat us out, and normality returned as rapidly as it had left us. The wind over Snowdon must have been far higher than the 5 knots Caernarfon were giving. I suspect an inversion was causing a 'vortex', funneling the wind through a narrow gap between the air masses over the summit. A similar meteorological effect caused the crash of a friend of mine in a Cessna 150  in lee-side sink into the flank of Kinder Scout. He and his student survived with minor injuries; the aeroplane was wrecked.

Link to crash of G-BFRP kinder Scout, 1983

Interesting discussion on lee-side wave and rotor

Lee-side wave, causing lift and sink, and also in the right conditions, vicious rotor in the shear between the air layers below the summit is a fascinating subject. Glider pilots exploit wave to soar to amazing heights, many times higher than the mountains originating the wave, and indeed I have often exploited this in the Chippy over Shropshire in the lee of the Welsh hills.

Here's a great description of wave and rotor from an experienced Glider and Tug pilot in Canada, and a video of wave and rotor over Fuji:

I have many years of gliding and towing in the lee of the Canadian Rockies. The rotor occurs downwind of the upgoing air, underneath the "crest" of the wave, where there is shear between the wave airmass and the underlying air. The rotor is often marked by very ragged, wispy, dark clouds, that are visibly rotating. 

The rotor can be extremely rough and quite violent. A very experienced tow-pilot friend of mine used to say "The rotor's not rough until you get rolled inverted!" 

Typically, the rotor only occurs at or below the ridge level of the mountain range that is generating it. The largest gust "jolts" I have experienced while flying commercially in the western US and Canada, have been while climbing or descending through the altitude of adjacent mountain ridge lines, on windy days. Based on my "Chipmunk calibrated posterior", I estimate some of them to have been ~2G. Quite scary for non-pilot passengers.

A typical wave-tow consists of flying up-wind through the rotor until you reach the upwind side and then turning to track parallel to the mountain front and climb in the disorganized lift until the air becomes magically smooth. At this point, the glider releases and by the time the towplane has done a 180, the glider is a 1000' or more higher.

The laminar flow in a wave is uncanny. Often the only indication in a glider that you are moving, is the altimeter winding upwards.

PS I've never towed into a wave associated with isolated peaks, but I've seen the so-called "UFO" lenticulars that form downwind of the Cascade volcanoes, like Mt. Rainier. I would image the rotor associated with those waves might be even more violent, because of air coming around the mountain, as well as over it.

Here is a nice time-lapse video of cap clouds and lenticulars at Fuji, although the labelling at the beginning is wrong. What is labelled as "Rotor Cloud" is the stack of lenticulars, marking the laminar wave. The actual rotor can be seen as fast moving wispy clouds, just above the foreground ridgeline. There is a good example at 0:25:

Time lapse of wave and rotor over Mount Fuji

It is more than likely that the day of the BOAC accident would have been a "blue wave day", where there was not enough moisture in the airmass to form clouds, so there would have been no visual warning for the crew of what they were flying into.




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