Red Face Time
All right,I *know* its only Thursday,but what the hell.
Last week I showed how the steam up is *supposed* to go. In practice,its different.
One evening,looking at the spanking new loco,sitting on the dining room table,I reasoned that if it stayed there much longer my will power would evaporate,and it never *would* move under its own power.Then I really would be like Father,a builder and exhibitor,but never a driver. The blokes in the club were already asking me with a puzzled air,when he was going to steam his stuff,to which I replied I had no idea.I still havent,and he never has. So I repaired to just outside the garage(not in it,its wooden) found two blocks of wood to rest the front and rear buffer beams on,so the wheels were off the ground. You can do this easily with a tank engine,a tender engine is a bit more complicated,due to the necessity of hooking up the tender with its water connections.It therefore would need blocking at the same height.I collected all the bits and pieces,filled the tanks with warm water,and pumped the boiler half a glass full,topping up the tanks again.Oiled round,motion work,axleboxes,coupling rod ends etc.
In with the kerosene soaked charcoal,fan on light up..BOOM off goes the fire.Smoke EVERYWHERE.All went well although slowly,until I had enough steam to run the engines own blower. Then pressure fell off.The fire was nearly out.On with the fan again,more wood(I'd run out of charcaol)soaked in kerosene more coal,up went the pressure,fan of blower on,and this time the pressure stayed up.I'd got more coal on this time.Then look at the water gauge....shit....hardly any water,pump some more in, cold,down goes the pressure,more coal,more smoke,pressure coming up, its *got* to be easier than this.....
After about half an hour I'd got the safety valves sizzling,eighty pounds on the clock.Open regulator.Nothing.Ah! but with only one cylinder it may be on a dead centre.Rotate wheels.Nothing.Then one notices that the reversing lever is pointing an accusing finger...straight up! Still in mid gear.Lever in full forward gear,open throttle *again*... Nothing.Meanwhile fire dying down,water level dropping,in the tanks as well,top these up,stoke,etc etc.
Finally,in desperation *push* the wheels round.BLAM!!!Everything disappears in a blur of noise and motion.Runs OK flat out,but you can stop the wheels with your finger(dont try this at home,kids), and it will *not* tick over.And the pressure *will* keep dropping. If it does this with no load it will assuredly never pull me. Put everything away,drop the fire,blow down the boiler,retire puzzled for a beer.
Turning the engine on its side to check the motion work,which is between the frames(it wasnt unknown for a fitter to get stuck on full sized jobs while adjusting inside gear,necessitating the complete dismantling of the valve gear to get him out),I noticed that in full gear,the valve rod was travelling in the opposite direction to the piston rod,while the latter was only about half stroke.I'd actually got the valve timed about ninety degrees out.The valve is supposed to begin its return stroke before the piston reaches dead centre, to provide"lead steam".This is steam admitted to the cylinder,to cushion the piston as it reaches dead centre.Either end,its double acting dont forget.Undo the big end from the crank axle,provide air to the cylinder.Push the piston rod right in,and put the crank axle at dead centre position.Then rotate the forward gear excentric until the rod shoots out.Refasten the excentric,and repeat in full back(reverse) gear.
After this treatment,it went much better,this time on the club track,but pressure still dropped more than it should.In fact, it should *gain* or at least maintain pressure with the load I was asking it to pull.And the water consumption was more than the axle pump could cope with on its own,so I had to continually resort to the hand pump in the RH tank.
So i built a four wheeled driving truck,a vague,though recognisable, replica of the traditional English RCH(1921) four wheeled wagon. The club trucks were really heavy bogie jobs for giving kids a ride, and weighed a ton.
Better again,but still not right.I could only manage two circuits of the club 440 yard track before I had to stop to stoke and regain pressure,as well as getting some water into the boiler. Finally,I opened the smokebox door to have a butcher's inside. I suspected the blastpipe.I *thought* maybe the blast nozzle was the wrong size.The trouble is,if you change the size of the blast nozzle, you also have to change its height beneath the chimney top.There is a definite relationship,bigger nozzle,higher up,smaller,vice versa. The "cone" of exhaust steam has to fill the chimney,leaving no gap to allow air back down as it goes up(thus destroying the vacuum in the smokebox) but at the same time you want it *all* up the stack,not creating back eddies in the smokebox.A lot of work was done at Swindon,by a bloke called Sam Ell,on locomotive draughting,which proved thatthere was more to the blast nozzle than drilling a hole in a bit of pipe and poking it up the chimney.And a lot of shy steamers were made to perform as they should when he redraughted them. Trouble was,nothing really made it any better.A smaller blast pipe cap(nozzle) induced a teriffic fuss,in fact the thing sounded like a pissed off moggy,but the back pressure was too great,and a larger cap wouldnt draw the fire.So I'd got the right size in the first place, more or less.Whilst gazing gloomily down the chimney,with the smokebox door open,I thought that the nozzle didnt look quite central. So I turned a lump of brass a push fit in the chimney,and drilled a hole in it,centrally,whilst still in the lathe.Then I turned a point on a bit of steel rod which fitted down the hole in the brass bit.The nozzle wasnt not *quite* central,it was distinctly wonky. So....make a blank nozzle cap,put marking blue on its top face,insert rod through hole in brass chimney plug,tap wiv an 'ammer,and drill nozzle as indicated by the mark.Bingo!Problem solved.
On its last true outing,the little engine raced round the track for half an hour(the last ten minutes in the dark,torch in hand),fuel and water consumption very frugal,and lever next notch from middle. Purred like a contented cat it did,chucked sparks ten feet in the air.This,however was only after I'd corrected the other problem. This was that the fire *would* die on me.I finally realised that although I thought I was putting loads of coal on,the sheer small size of the shovel I'd made meant it wasnt enough.A bigger shovel cured the problem.The current shovel is huge.All off an inch and a quarter long:-)
Its very rewarding,after all the work(in itself a pleasure)to see the reaction of the general public.All the time your are building the thing in the shed,you're regarded as a bit of a nut,by friends, neighbours,Uncle Tom Cobley and all.But when the kids ask their dads "Why cant YOU make one of those,dad?",and see Dad's sickasaparrot expression its well worth while.And as well,its a strange thing,that the kids love 'em even now.they've never *been* steam hauled in their lives,but they still flock round"Can I have a ride,mister?". We once had a club steam up on a day when a travelling fun fair was operating outside the track site.In the end we had to give in to pressure and offer the kids rides at ten pence a go,even if it *was* supposed to be a private do.We did much better than the fun fair that day.
If you come across a Live Steam tracksite which is operating(miniatures I mean),go and have a look.There are clubs both in the States,and in Canada too.No Model Engineer minds answering intelligent questions, any more than Land Rover owner do in similar circumstances,and they, like Rover owners,are always keen to rope in another suck....ah, enthusiast.You may even get a ride.One thing you *cant* do,is preserve any dignity at all,being driven round behind a tiny loco, grinning ear to ear.The club stopped calling the gatherings"Steam Ups" in the end.Hell,we were just playing trains!