[Marion Michie]

My son purchased a 2nd hand Hornby Real Steam Stephenson's Rocket 3.5" gauge. We have followed all the instructions, oiled it etc it lights and the water boils, but when we try to 'push it off' the front wheels are locked and it won't move. This is the 2nd attempt. The first time it actually moved by itself slightly but then stopped, but my son had set the track up on our grass, which is not very even so I presumed it needed a flat surface. Does anyone have any ideas what might be wrong. My son is 8 years old and although he knows a fair bit about trains and knows a lot more than me, he doesn't know what to try. I hope someone will be able to help. Thanks Marion

 

[34C]

Does it roll when cold, try both forward and backward? Sounds like a simple mechanical fouling that prevents movement. If you cannot see anything obstructing either the wheels from turning or the sliding motions of the piston rods, by external examination, then it may be necessary to look inside the cylinders to see if one of the piston movements is being obstructed there.

Never having owned one of these devices, that's all I can suggest directly. A web search using terms like 'Hornby live steam rocket problems' may turn up some experience from other users.

Good to hear of an 8 year old with a steam engine BTW, I learned a lot from my Mamod at that age.

 

[Dinwiddy]

Hi

If i remember correctly the two main wheels actually have a 2:1 reduction gearing inside the centre so that the wheel only makes one revolution for each two cycles of the cylinder. It would seem likely from your description that one or both have jammed. Try and check the hub gearing on each wheel as even a small piece of grit can jam it very effectivly.

Hope this is helpful.

David Y

Loco-notion Models

 

[jcuknz]

I somehow doubt the suggestion of gears in the wheels as neither the original rocket had them or this video of one in action.

and

The second track is not very level and Rocket seems to cope well.
In making smaller cylinders than this obviously has the passange of the piston has to be smooth up and down and rather than steaming up you need to check the action of the loco when cold so you don't get burnt fingers. Helping matters with oil. A dirty task an 8yo will enjoy for sure.
Not sure an 8yo has the skills to source the problem and you need outside help. I'd try and find a member of your local Model Engineering Club

edit This shows a replica at work, nice CU of piston and valve motion near start

 

[Petal]

QUOTE (jcuknz @ 2 Oct 2013, 06:06) <{POST_SNAPBACK}>I somehow doubt the suggestion of gears in the wheels
........
........
edit This shows a replica at work, nice CU of piston and valve motion near start

If you read through the comments in the last link you will find a reference to the fact that the reduction gears have been removed which sort of confirms that the Hornby models did have reduction gears.

 

[LTSR]

I've not been close up to one of these Hornby models but I do know a little about live steam so I'm guessing that the models did not have any gearing. After all one of the advantages of steam power is that it develops maximum torque from stationary thereby rendering gearing unnecessary.

I suspect that the problem may lie in a derangement of the timing of the valve events that admit and exhaust the steam from the cylinders.

Without going into too much detail and for a quick check observe each cylinder in turn and see if the piston rod and valve rod behave in a similar manner at each end of the piston stroke. What you should see is a similar and equal pattern of movement at each end of the piston stroke.

There are other possibilities; could you be getting so much condensed steam in the cylinders that you are getting a hydraulic lock?
Also are you overfilling the boiler so that you are sending solid water to the cylinders rather than steam?
I doubt these things come with drain cocks!

You could do worse than have a look at http://en.wikipedia.org/wiki/Stephenson_valve_gear to help you gert your head around the way it works.

 

[jcuknz]

The motion does seem to be going rather faster than the driving wheel so I guess that my earlier comment about gears was wrong.
Definitely think one needs to get the loco free moving when cold before adding steam, fewer burnt fingers.
My searching brought up interesting info about its history ... thanks for posting Marion even if we have not solved your son's problems.

 

[Long funnel & tiresome]

Sorry I can't offer anything constructive about the Hornby live steam model's problem, though the videos of the locos actually working looks as if it will prove to be a wonderfully exciting experience for your son.

In checking the videos linked to the thread, I particularly enjoyed this maverick video of "Dampfspieler" dicing with death behind his beautiful live steam Rocket. Notice how he uses his hands for added propulsion and, above all, where he places the gas bottle....
Perhaps Steamplayer and his version of the Rocket did actually manage to escape the Solar system!

LF&T

 

[Cookie 1]

I have the rocket buy of ebay, I replaced the burner it steam up well but not have the power to run itself on a track, if I lift the wells of track it turn real good , just done seam to have the power

 

[34C]

If this is a well used specimen, it could be badly worn so that the steam leaks past the pistons in the cylinders, rather than generate enough power ro move the loco. With the driving wheels lifted off the rails not much power is required to turn them, so then they spin.

Does the loco and tender roll freely when cold?

 

[dwb]

I have one of these but rarely had it in steam and certainly not for many years. As I remember, it could barely pull itself along the track when new, so I don't think your experience is unusual.

David

 

[Cookie 1]

do you think it need running in more

 

[34C]

do you think it need running in more

Sorry Cookie, none of us are in a position to help you directly, because only you have the item to assess and experiment with. You are going to have to be the practical engineer to systematically explore what is required to make it work. The good news is that the mechanism will run with the driven wheels off the rails, that suggests there is nothing seriously wrong, it just needs some attention.

First suggestion, just the loco, not in steam (cold), does it roll freely on track? If not, that has to be fixed. This may only require correct lubrication on all moving parts, check whatever product instructions you can find for all the lubrication points and correct lubricant. There possibly could be damage somewhere preventing or limiting free movement, if so that has to be found and fixed. And test under steam.

Still not working?
If you read what was posted earlier in the thread, there are suggestions about checking the valve gear to ensure it is functioning properly. Since the loco appears to raise steam satisfactorily, that's what I would l check next, following the leads suggested in those earlier posts.

All the best with it.

 

[Cookie 1]

it run good with out steam , run good with steam but not the power to pull it self . I use good quality steam oil, it not have the steam pressure it needs to run , I boil the distilled water be for filling to help heat up quicker and not wast gas

 

[34C]

... it not have the steam pressure it needs to run...

If that's the case and you are sure there are no steam leaks and the safety valve isn't lifting, needs greater heat supply. As ever, be careful and wear appropriate protection because even a small failure of a pressure vessel can inflict painful injury. (I assume Triang over-engineered the presurised components, but it is now many years from leaving the factory...)

 

[dwb]

As ever, be careful and wear appropriate protection because even a small failure of a pressure vessel can inflict painful injury. (I assume Triang over-engineered the presurised components, but it is now many years from leaving the factory...)

That's another thing that makes me wary of steaming mine again.
If this was the kind of live steam engine that you'd run at a model engineering society, you would need to have both a hydraulic pressure certificate and a steam certificate before they will let you anywhere near the track. All clubs have the means to perform these tests and the qualified personnel to administer them. Maybe a visit to a local model engineering society to find out what's required?

As to the power available to pull it, how much force is required to stop the wheels from turning when the loco is not trying to haul itself around? If it's a reasonable amount them maybe trying to reduce friction in the various moving parts might help.

David