GWR..ish Castle..ish

[Riograndad]

Continued work on the narrow gauge (rivet counters beware...!) Castle today. Decided to get the shape of the tender done to see how the proportions of the loco are looking. The tender helps I think.

View attachment 281018 View attachment 281019

Looking good,yes the tender helps,also like the pics of the railcar,interesting take on things!!!!

 

[ge_rik]

Really enjoying this thread. I'm a great fan of '.... ish' builds.

Rik

 

[jimmielx]

Quite a bit of progress, though not terribly obvious in the pictures!

But: the cab sides and floor are now fixed; the tender now has wheels - outer pairs of ball bearing pickup wheels and the centre wheels flange-less and flattened; various white metal bits placed; the speaker will go in the tender, accessed through a removable top plate at the back; firebox has another sheet of thin ply over it with some detail; and holes drilled for cable runs through the firebox.

The decoder and smoke generator will go in the boiler, so fittings for those are on the list. As is a smokebox door, cab interior and roof, rivets, rivets, rivets, wiring, coupling between loco and tender, splashers... and the motion...

Feeling happy with how it's going so far. A lot to do!

 

[jimmielx]

Started work on the motion. I've needed to scale this up a bit, because of the plastic strip I'm using to make it to give it a bit of strength and because the cranks on the Thomas wheels are a bit further off centre than on the prototype. The advantage of this being an imagined narrow gauge homage to the prototype is very useful at time like these!
The sliders are just plasticard strips, the crossheads are made of plasticard cut out on a vinyl cutter and then ply-ed together. It all feels pretty robust, but time will tell.

 

[jimmielx]

And fitted to a cylinder. The connecting rod angles back a bit to allow for the big lateral movement of the Thomas wheels...

 

[jimmielx]

Given the motion a quick test today. I think that get's a pass.

However as pointed out earlier in the thread I'm going to have to work on the front bogie (is that what it's called? I think it's not a pony truck). The rear wheel of the bogie is just catching the inside of the cylinder on the R2 curves, it's also only articulated at the body join so that is just forcing it off the rail.

My thought is to add an articulation point where the arm from the body meets the bogie. Does anyone have a loco with a similar wheel arrangement? I'd be interested to know how a G scale model might usually do this. My Hornby A4 Pacific has the two articulation points, so that's probably favourite at the moment. I imagine the prototype is centrally pivoted with some lateral movement allowed somehow, I guess something like that could also work, I just wonder how I ensure the lateral movement is reliable. I also imagine the prototype doesn't have to negotiate R2! Here's what I currently have (minus one of the cylinders but you get the idea)... Any thoughts gratefully received.

 

[dunnyrail]

Yup it is a bogie.

 

[jimmielx]

Seek and ye shall find ...

K4 misc info/tips

This is most useful food for thought! Thanks Greg!

 

[a98087]

cracking modelling!
The double pivot idea would probably work as I’m sure I’ve had locos in various gauges that used it.

Dan

 

[Paul M]

Wouldn't just moving the pivot point work?

 

[dunnyrail]

Wouldn't just moving the pivot point work?

Perhaps as far forwards as it would go and a double pivot may be the get out if jail card.

 

[Rhinochugger]

Given the motion a quick test today. I think that get's a pass.

However as pointed out earlier in the thread I'm going to have to work on the front bogie (is that what it's called? I think it's not a pony truck). The rear wheel of the bogie is just catching the inside of the cylinder on the R2 curves, it's also only articulated at the body join so that is just forcing it off the rail.

My thought is to add an articulation point where the arm from the body meets the bogie. Does anyone have a loco with a similar wheel arrangement? I'd be interested to know how a G scale model might usually do this. My Hornby A4 Pacific has the two articulation points, so that's probably favourite at the moment. I imagine the prototype is centrally pivoted with some lateral movement allowed somehow, I guess something like that could also work, I just wonder how I ensure the lateral movement is reliable. I also imagine the prototype doesn't have to negotiate R2! Here's what I currently have (minus one of the cylinders but you get the idea)... Any thoughts gratefully received.

View attachment 281908 View attachment 281909

I'd be tempted to separate the bar from the bogie, and link it via a pivot point just behind the front bogie wheels - say about 1/3 rd of the way back.

If I've got my thinking right, that should minimise the amount of swing in the rear bogey wheels.

The other way to cheat, is to take a bit off the inside of the cylinders - the bit that nobody will see

 

[PhilP]

Yep! I'd pivot the truck/bogie to the arm.. Also probably add some weight? - They can be a little 'skittish', if not controlled.

PhilP

 

[jimmielx]

Thanks so much for all the replies, really appreciated!

I'll add a pivot on the arm near the bogie, that should be the simplest thing to try first.

Unfortunately the arm itself runs right through the bogie, so I'll have to do the pivot at the back and see how I go. I've got a feeling that might give the clearance needed too, but if not I will take some chunks out of the back of the cylinders!

I've got some weight on the bogie already, but will try to add more - currently the wheels are plastic - because I had them in a drawer and were easy enough to adapt to inside frame - I could look into metal wheels for extra weight too if needed.

 

[dunnyrail]

Thanks so much for all the replies, really appreciated!

I'll add a pivot on the arm near the bogie, that should be the simplest thing to try first.

Unfortunately the arm itself runs right through the bogie, so I'll have to do the pivot at the back and see how I go. I've got a feeling that might give the clearance needed too, but if not I will take some chunks out of the back of the cylinders!

I've got some weight on the bogie already, but will try to add more - currently the wheels are plastic - because I had them in a drawer and were easy enough to adapt to inside frame - I could look into metal wheels for extra weight too if needed.

I think metal wheels would be a big help.

 

[jimmielx]

Progress was halted a bit last week, but all going again now!

First of all thanks for all the replies re the bogie. I've added the second articulation point and it seems to run very much better - an added bonus is a tiny bit of upwards downwards movement too which I think will help the ride. I'm going to stick with the plastic wheels for now as I think they look ok, and the bogie itself has a fair amount of weight on it already, however they are on the list to swap if I get any more problems there.


And on top I've pretty much reached the stage where I will start the painting process next. For me that's sanding sealer, rivets, primer spray, colour brushed on, varnish, lining, varnish. And somewhere within that wiring and more detailing. I've got mounting points for the decoder, speaker and smoke generator in already and a route for the cables, so hopefully the electrics will be straight forward enough.


I've also made a start on the cab back end (which is not yet stuck in), a bit more to do there too.



Really looking forward to getting some paint on it finally, but even looking at the pictures reminds me of a few things to do...!

 

[jimmielx]

The other way to cheat, is to take a bit off the inside of the cylinders - the bit that nobody will see

I also took a chunk out of the inside of the cylinders - and indeed you'd never know! Thanks!!