The Heybridge Railway, 1889 to 1913

Reader mode
Osgood

Osgood

Western Thunderer
The top rollers on the jib stays would be fine if the hoisting drum were high up as on the Ruthin example, but not for the Peco layout, so chain should be moved down.

If you were to take the small gear wheel and put it on the brake side end of the big gear shaft, get another big wheel and place behind the brake drum, you’d have a viable mechanism.

But to be quite honest your completed model looks flippin’ good and who is going to know (so long as you move that chain down!).
 
Richard Gawler

Richard Gawler

Western Thunderer
Osgood said:
The top rollers on the jib stays would be fine if the hoisting drum were high up as on the Ruthin example, but not for the Peco layout, so chain should be moved down.

If you were to take the small gear wheel and put it on the brake side end of the big gear shaft, get another big wheel and place behind the brake drum, you’d have a viable mechanism.
Click to expand...

There is no space to relocate any of the gears, they have to stay put. I suggest, the winding drum needs to be on the axis of large gear. Doing this gives a suitable mechanical advantage to the brake and to the handle.

DSC_7050.jpeg
I agree, this gives a better overall effect; but I will always know the mechanism has no basis in engineering. Altering it now looks so difficult it would be easier to build a new kit and transfer the jib and stays across.
 
Osgood

Osgood

Western Thunderer
What it also allows is for the smaller hook to be used with the chain resting draped over the rollers as in real life - so long as the vertical run down to the hook is straight it will look the business. :thumbs:
 
Richard Gawler

Richard Gawler

Western Thunderer
simond said:
I’ve just noticed that there is no mechanical advantage in the large gear. I’m sure the real one wasn’t like that.

Can’t understand why Peco would do that.
Click to expand...

simond said:
Yes, I’m sort-of sorry I posted the comment about mechanical advantage, thought about it at the time, decided to “publish & be damned”

I do hope I’m not too damned!!!
Click to expand...

When criticism is necessary it is necessary! Without such criticism, if I post an incorrect model (however innocently) and people proceed to simply hit the "like" button this can only serve to reduce the value of WT. If I am to grumble at all, I wish someone could have pointed this out earlier; but I can blame only myself for coyly hiding the winding drum out of sight in my main photograph.

I see two options to make the model better:
  • Move the winding drum onto the axle carrying the large gear and let the chain run over the rollers I have strung between the guy rods. This would make a more prototypical model.
  • Put a new roller on the top of the jib and run the chain over this; and dispense with the rollers between the guy rods. This is a lot easier to do.
If the model was made out of brass I could dismantle things, reassemble and repaint. But this creation is a mixture of wood, metal and plastic, a little fragile in places and difficult to rebuild. I might have a go at a fresh kit another day; but in the meantime, I'll go for the lower roller.

If anyone knows that the chain should exit from the bottom of the roller not the top, or the crane should have a steel cable not a chain, now would be a good time to mention it :))
 
Richard Gawler

Richard Gawler

Western Thunderer
Osgood said:
What it also allows is for the smaller hook to be used with the chain resting draped over the rollers as in real life - so long as the vertical run down to the hook is straight it will look the business. :thumbs:
Click to expand...

Maybe yes, maybe no. The trouble is, the small hook weighs 0.8 grams, probably less than the chain immediately above it. The Mecanno hook weighs 3.9 grams. I can experiment, maybe make a third hook from metal.
 
Osgood

Osgood

Western Thunderer
Cranes of this era used mostly chain as wire rope development was still in its infancy, look at the steam rail cranes of this period for example.

Reeving of the chain on the drum would usually be as you have it - pulling over the top of the drum, as evidenced by period photos of yard and mobile cranes.

Sometimes a split additional weight (spherical or elongated) called a dumbbell would be clamped to the cable / chain above the hook to help lowering.
 
Last edited:
Phil O

Phil O

Western Thunderer
The chain taking the load needs to take the most direct route between the winding drum and the jib wheel, the weight of the load will bend the spreaders of the jib stays.

Rollers have substantial support to take the loads involved.
 
simond

simond

Western Thunderer
Richard Gawler said:
When criticism is necessary it is necessary! Without such criticism, if I post an incorrect model (however innocently) and people proceed to simply hit the "like" button this can only serve to reduce the value of WT. If I am to grumble at all, I wish someone could have pointed this out earlier; but I can blame only myself for coyly hiding the winding drum out of sight in my main photograph.

I see two options to make the model better:
  • Move the winding drum onto the axle carrying the large gear and let the chain run over the rollers I have strung between the guy rods. This would make a more prototypical model.
  • Put a new roller on the top of the jib and run the chain over this; and dispense with the rollers between the guy rods. This is a lot easier to do.
If the model was made out of brass I could dismantle things, reassemble and repaint. But this creation is a mixture of wood, metal and plastic, a little fragile in places and difficult to rebuild. I might have a go at a fresh kit another day; but in the meantime, I'll go for the lower roller.

If anyone knows that the chain should exit from the bottom of the roller not the top, or the crane should have a steel cable not a chain, now would be a good time to mention it :))
Click to expand...
Can’t help with those questions, but I think your idea of building another crane to use the plinth you have at some indeterminate point in the future is probably what I’d do. There are some other kits on the market which might appeal.
 
Richard Gawler

Richard Gawler

Western Thunderer
Phil O said:
The chain taking the load needs to take the most direct route between the winding drum and the jib wheel, the weight of the load will bend the spreaders of the jib stays.

Rollers have substantial support to take the loads involved.
Click to expand...

DSC_7053.jpeg
If my crane had its winding drum at the top, the rollers on the spreaders would support the chain when the hook was unloaded. They would stop the chain sagging onto the jib. During operation, the tension on the chain would lift it clear of the rollers. These rollers and spreaders are redundant on my model.

Osgood said:
You could always add a roller, mounted 1/2 way up the jib on a simple iron support bracket?

View attachment 218926
Click to expand...
Conversely, the type of roller suggested by Tony could be located such as to stop the unloaded chain dragging on the jib, or to take the weight of the chain under load. I have not found any photographs of such a roller, and while I have now made a roller I won't make a mount for it unless I know what the whole arrangement is supposed to look like. The model cannot suffer any more from multiple design inputs (Peco, me and WT) each related to a different style of crane.
 
4

40057

Western Thunderer
Richard Gawler said:
View attachment 218981
If my crane had its winding drum at the top, the rollers on the spreaders would support the chain when the hook was unloaded. They would stop the chain sagging onto the jib. During operation, the tension on the chain would lift it clear of the rollers. These rollers and spreaders are redundant on my model.


Conversely, the type of roller suggested by Tony could be located such as to stop the unloaded chain dragging on the jib, or to take the weight of the chain under load. I have not found any photographs of such a roller, and while I have now made a roller I won't make a mount for it unless I know what the whole arrangement is supposed to look like. The model cannot suffer any more from multiple design inputs (Peco, me and WT) each related to a different style of crane.
Click to expand...
I’ve never really thought about crane design before, so the exchanges here have been very educational. But looking at your photo above with the ruler, I don’t think the Peco designer knew any more than me. The various components only make sense if the winding drum was on the top wheel.

I’m reminded of the nonsensical wagon brake gear which has appeared on many models, presumably down to the designer/manufacturer not understanding the mechanism. That I would spot, the crane I wouldn’t have done — before now.

Thank you for my improved understanding!
 
Phil O

Phil O

Western Thunderer
Richard Gawler said:
View attachment 218981
If my crane had its winding drum at the top, the rollers on the spreaders would support the chain when the hook was unloaded. They would stop the chain sagging onto the jib. During operation, the tension on the chain would lift it clear of the rollers. These rollers and spreaders are redundant on my model.


Conversely, the type of roller suggested by Tony could be located such as to stop the unloaded chain dragging on the jib, or to take the weight of the chain under load. I have not found any photographs of such a roller, and while I have now made a roller I won't make a mount for it unless I know what the whole arrangement is supposed to look like. The model cannot suffer any more from multiple design inputs (Peco, me and WT) each related to a different style of crane.
Click to expand...


That looks one helluva lot better and plausible, than the chain passing over the top of the spreaders, now that the load is moved directly from the head of the jib to the winding drum, even if the winding drum, is not in the prototypical position.
 
Phil O

Phil O

Western Thunderer
Part of my boilermaking career involved working with the structural elements of cranes that were onboard RN and RFA ships, we had a separate department, that dealt with land based and mobile cranes. I don't claim to be the font of all knowledge with regards to cranes, but I do have a working knowledge of the practicalities of them.
 
simond

simond

Western Thunderer
I remember reading the operating manuals for cranes, slinging, lifting etc., when I was an undergrad engineering trainee at the shipyard

Two things stood out:

You must never try to lift an immovable object.

You must always properly support the load before unhooking it.

Now, I moved into the Railway and Automotive industries after graduating, so I didn’t have too much to do with cranes subsequently, but I’ve remembered these examples of sage wisdom, and they’ve always stood me in good stead - I commend them to you.




:)

(They were both in the lifting manual for shipwrights)
 
Reader mode
You must log in or register to reply here.
What's New?
Top