7mm David Andrews Princess - 6206 Princess Marie Louise

[Yorkshire Dave]

This is one of these experiences which falls into the 'benefit of hindsight' category - and one for memory should this re-occur.

One solution would have been to re-engineer the rear of the frames by making up another set from scrap etch and solder them on the inside at points X. Then cut away the magenta bounded area of the original frames leaving an inset. This could either be left or filled with plasticard or tissue paper soaked in superglue.

 

[simond]

Rob,

I had missed that you were using American pickup. You’ll have guessed from my “diagnosis guide” that I’m far from a fan, though it probably works well on bogie diesel/electric locos or mu’s, and clearly you have made it work for you in previous builds.

I think the Slaters insulated hornblocks with split axles is the way to go if you don’t want to use rim pick-ups, but of course there is some added labour involved!. I’m quite happy with rim pick-ups, using the design I developed from David LO Smith’s drawings, in most cases.

cheers
Simon

 

[Rob Pulham]

Hi Gents, I didn't reply yesterday as I am only part way through the saga relaying what I did retrospectively having only taken photos as I went along without writing them up.

All issues of whether the styrene might wear over time aside, even with added weight on the trailing truck, the chassis still wouldn't go around a 6ft curve reliably so more drastic measures were needed.

Using a piercing saw I cut out part of the inner frames.



Then I soldered a plate across the ends of the frames at the front by good fortune there were two tabs at the rear with could be soldered to.





I then reduced the width of the inner plate and soldered the frame pieces back together with some end plates to take up the gap left by the saw kerf.





A quick dry fit of the rear truck leaves plenty of space either side of the inner swing so there should be no shorting but I may need to remove some of the spring casting to allow more swing to help it get around the curve - it's a long chassis.

 

[Yorkshire Dave]

I may need to remove some of the spring casting to allow more swing to help it get around the curve - it's a long chassis.

If the castings can be removed from the truck frames I would thin them slightly from the rear so they at least retain the front detail and sit flat on the the truck frames.

 

[chigley]

checked mine, similar prob

 

[Rob Pulham]

Well, I got there at last. Her Royal Highness will now go around 6ft curves without derailing or shorting.

I did have to introduce some springing to restrict the movement of the bogie.



There are two spring wires at the rear which fit between the inner and outer bogie frames. They restrict the sideways movement of the rear of the bogie. The bogie pivot point has side control springs which allow more movement at the front of the bogie. This sort of worked but the front of the bogie was so light that it had a tendency to lift of the track so I added a second element of springing which holds down the front of the bogie and all runs nicely. This spring has a loop which is held in place by the pivot screw then bends over the front of the plate that you can see in the image below before curving onto the front of the bogie frame. Although it looks huge in the enlarged image it's only 0.5mm spring wire.

 

[Clarence3815]

Colour scheme?

 

[Rob Pulham]

A few photos of the state of play before I strip her down and pack her up for painting.

 

[OzzyO]

Hello all,

the Princess's always look long even compared to a Duchess, I don't think that there is much in it to which one "is" the longer.
I think the the Princess look long due to the diameter of the boiler.
Nice looking build Rob.

ATB

OzzyO.

 

[Rob Pulham]

Thanks Paul,

The Princess wheelbase is 6" longer that the Duchess I think.

 

[Lancastrian]

Princess - 74' 4 1/4"
Coronation - 73' 9 3/4" (streamlined), 73' 10 1/4" (non-streamlined)

 

[LarryG]

The Princess's were fav's of mine because they looked like other LMS taper locomotives but were vastly more impressive looking. When you saw one as you approached a station, you knew why.

 

[OzzyO]

Princess - 74' 4 1/4"
Coronation - 73' 9 3/4" (streamlined), 73' 10 1/4" (non-streamlined)

Do you know why the streamlined ones were shorter by 1/2" and did they stay like that when the streamlining came off?

ATB

OzzyO.

 

[simond]

Princess - 74' 4 1/4"
Coronation - 73' 9 3/4" (streamlined), 73' 10 1/4" (non-streamlined)

I do not understand why it should be the case, but the real difference of only 6 inches does not explain why the Princesses appear so very long.

The Duchesses appeared, to me at least, beautifully, even perfectly proportioned, I was never fond of the Princesses.

 

[timbowales]

I do not understand why it should be the case, but the real difference of only 6 inches does not explain why the Princesses appear so very long.

The Duchesses appeared, to me at least, beautifully, even perfectly proportioned, I was never fond of the Princesses.

Optical illusion caused by the thinner boiler?

 

[simond]

I guess so, I can think of no other rational explanation!

 

[mickoo]

The boilers are externally the same between the two classes and smokeboxes the same diameter (but Coronation is shorter)....give or take an odd 2-3/8th".

The Coronation boiler sits higher so has a shorter chimney, the firebox is also larger which shunts the front end forward so the front platform is shorter than the Princess Royals.

 

[Yorkshire Dave]

Not only the boiler pitch as @mickoo alludes to, the illusion of the extra length is also completed by the cylinder position, lack of smoke deflectors and the uneven coupled wheelbase (8'+7'3'') on the Princess Royals. (Princess Coronation/Duchess coupled wheelbase is 7'3''+7'3'').

 

[mickoo]

Not only the boiler pitch as @mickoo alludes to, the illusion of the extra length is also completed by the cylinder position, lack of smoke deflectors and the uneven coupled wheelbase (8'+7'3'') on the Princess Royals. (Princess Coronation/Duchess coupled wheelbase is 7'3''+7'3'').

Even when running without deflectors, the Coronations have more bulk, I think the outside cylinder steam pipe covers are a part of that visual aspect and the cylinder position as you say, almost certainly plays into that as well.