Atlantic's works: Portable layout - Ground Signals Again

[Atlantic 3279]

Another digression from the A2/3 job this morning, but since an item arrived in the post that will, in due course, allow me to test the suitably of my resin A2/3 parts (plus a new running plate) as a means of turning a suitable Hornby A3 into the dreaded A1/1 Great Northern, I sensed another excuse for a picture:

This loco is from a complete Hornby "Talisman" set, so should anybody now wish to make me a genuinely interesting offer for the three mint, boxed, original-tissue-wrapped Hornby maroon "Talsiman" branded BR Mk1 coaches, please say so. The outer Hornby box is damaged (from postal rough handling?) at one corner, but the inner foam tray and the coaches are unscathed. You can have the loco headboard, certificate of authenticity (no 1650) and operating/maintenance sheet too if you wish.

[davidwest]

TBH Graeme, the A1/1 interest me far more than the A2/3. I've a DJH built and another with the chassis started.

[S.A.C. Martin]

Now this I am looking forward to seeing (and taking suitable notes!)

[Blink Bonny]

Ay up!

Go for it! Go on, better mine! You know you want to!

[Atlantic 3279]

A2/3 progress report: Cylinders in new positions on new stretcher. Motion bracket lower front corners shaped and completed, mounting to chassis completed and electrically split. Con-rods shortened and fitted to drilled crossheads. New thin backs added to slidebars and slidebar rear ends solder to motion brackets at correct inclination. Radius rods rivetted up to combination levers. Left side driving crankpin outer end re-slotted to make return crank lean the right way. Left side eccentric rod shortened and rivetted to lower end of expansion link.
Left side motion now all fitted up and working, right side should take little time to finish later today. Photos to follow......

I may yet have this second A2/3 loco fully assembled (if not painted) and available for interested parties to see "in the flesh" by the time of Caistor and Peterborough shows. Should be complete in every way in time for Leeds (if I go) or failing that for Spalding &/or Hull.

[Atlantic 3279]

Okay, second side of motion finished off painlessly in 15 minutes after tea today, and no signs of any binding or catching on back and forth running through my twistiest crossovers, so it's time for some more piccies and brief notes:

Firstly cylinders stuck to a multi-layer new plastikard stretcher as detailed in my first set of chassis-method notes, the old moulded stretcher being cut away once the first (top) layer of the new stretcher was firmly bonded in place. Make sure the cylinder tops have been filed flat but left rough so that the adhesive gets a good grip.
Also the shortened con-rods. The estimated excess length of the outer (fluted) layer was cut off at the little end, to take the fluted layer back in length to finish slightly short of the crosshead. The two-layer rods were then soldered together, the plain inner rod still projecting to full length at the little end. The short off-cut of fluted rod was then soldered onto the back of the sandwich, with its little-end eye in the correct new position, 29mm from the big-end centre. All that remained was to drill through the blind middle layer at the new little end hole, trim of excess, shape eges with files, ream holes to fitting size etc.

then drill the Bachmann crosshead to take a proper pin, the cast "pin" originally part of the crosshead being impractical for re-use when fitting a new con-rod. I put the head of my new pin at the inner aspect of the assembly, the shaft of the pin passing firstly through the con-rod, then out through a snug hole in the crosshead, into which I locked it with a spot of cyano, then cut off the projecting length.

[Atlantic 3279]

Metal top of motion bracket stretcher split with light use of piercing saw to electrically separate the two halves of the live motion. Slips of 5 thou plastikard glued on to isolate it from the running plate.


The 50 thou thick plastic under-layer added to the stretcher. Lower corners of outer brackets turned in ready for slodering to inner brackets (and ultimately to rear ends of slidebars too).


Parts of the Comet slidebars used to replace the previouslt cut-off thick plastic inner Bachmann slidebars. The return bends on these are soldered to only the last mm or two of the backs of the outer slidebars, the front ends of the new bars tucking away neatly on the outer face of the remaining stub of plastic slidebar at the rear of the cylinder. This can be carefully superglued too (don't glue up the crosshead in the process!), although once the rear of the slidebar assembly is also soldered to the bottom corner of the motion bracket, not much will be trying to move around anyway.


Don't forget of course that the crossheads must be in the slots before you add the backs of the slidebars, and the top rear corners of the slidebars need to be notched with a flie to allow the bars to sit at the correct inclination yet fit tightly againstthe lower corner of the motion bracket, as seen next.......

[Atlantic 3279]

Both stretchers now in place and radius rod rivetted up in situ to combination lever. Slidebars at estimated 1in 50 slope, or something like, and tight against bottom corner of motion bracket. With running plate on to keep stretchers frimly in place, and con-rod swung out of the way, quick pre-tinned "spot soldering" from beneath will make the slidebar-to-motion-bracket joint - plenty of iron-power, clean bit, clean work, correct hint of solder on bit, flux locally on job, in and out QUICKLY before heat spreads and wrecks other joints (or fries your fingers if you are using the "Mark 1 work clamp").
Although it may not be prototypical, you can deliberately splay out the rear ends of the slidebars to some extent before soldering them to the foot of the bracket - this will increase crosshead-to-leading-crankpin clearance to suit running on curves.

[Atlantic 3279]

Original notches in the outer end of the driving crankpin are top and bottom when the pin itself is at top (or bottom) dead centre:


As Bachmann make the return crank, which locates in these notches, of only one pattern for both sides of the loco, this results in the left return crank leaning the wrong way, as if for outside admission valve gear. The original eccentric rod (or the Comet V2 one for that matter) are also much too long for the A2/3 application:


With very careful use of the piercing saw, new notches (arrowed blue) can be cut about about 45degrees "ahead" of the originals (arrowed red) but a small undmaged "land" MUST remain between the two slot positions (arrowed green) otherwise the re-fitted return crank may start to flop uncontrollably back and forth:

[mick b]

Great pictures.

Made a start on my A2/2 today. I have started to fit a Hornby A4 cab into the A2 boiler . So far it matches all the dimensions I have and looks the part too as its a off a scrap current super detail version. it will even have opening cab vents and similar roof details too.
I have has to remove some of the footplate fixings from the A2 footplate and the floor from the A4 cab to fit so far. I still need to remove material for a final fit of parts. Some minor filling will be needed in due course.

Re the smokebox door on the A2 is easy to remove ? a tap from inside the boiler to loosen?


Now away till monday when some more work will be done.

[Atlantic 3279]

That's better......



Due to the large required size of the eyes in a thin rod, the eccentric rod cannot simply be re-drilled to 16mm centres and the excess length cut off at one end. It must be cut at an intermediate position, the excess length taken out, and then the ends soldered back together. The most practical way to do this is to add a backing layer across the joint - the "middle offcut" of rod is ideal for this backing piece. By aligning the pieces exactly on sticky tape ready for soldering, this fiddly job became a bit easier....
MAKE SURE that the cut in the rod is nearer the end that meets the expansion link, i.e. away from the return crank end. If you don't do this, your backing piece over the joint in the rod will foul the heel of the return crank as the crank rotates!

On rivetting the eccentric rod inside the foot of the expansion link, the motion is complete:


Giving this appearance so far overall to the left side of the loco.



Mechanism now successfully adapted, the more purely cosmetic considerations can now move on apace.......

[Atlantic 3279]

Hi Mick, I haven't tried tapping the door out of its nest from within - it may work, it may not. To save taking out the boiler weight, I put a blade behind the edge of the smokebox front at the bottom of the smokebox, and very carefully "tweaked" the joint apart, the brittle glue obligingly cracking (instead of the door) as I worked around the "bottom quarter" of the joint. The door/front then more or less fell out.

On the last one I did, it looked as if somebody had previously tried to get the smokebox front out, but had started with a blade high up on one side of the joint, going a little too heavily and cutting into the edges of the front itself, so I had to do some cosmetic repairs to that one.

[mick b]

Ok ,thanks for the info.
One guess who has already taken the boiler weight out !! So i will try the tap method first !!

[S.A.C. Martin]

On the last one I did, it looked as if somebody had previously tried to get the smokebox front out, but had started with a blade high up on one side of the joint, going a little too heavily and cutting into the edges of the front itself, so I had to do some cosmetic repairs to that one.

Just to emphasize - not done by me! That model went straight from its previous owner to your hands (though I suspect the damage may have been done by a particular centre of modification, in its renaming/numbering, and not by the previous owner).

It's looking really good Graeme. How much would need to be done at this point to turn the A2 into the A2/2 variant? Not much I'll wager...?

[Tom F]

On the last one I did, it looked as if somebody had previously tried to get the smokebox front out, but had started with a blade high up on one side of the joint, going a little too heavily and cutting into the edges of the front itself, so I had to do some cosmetic repairs to that one.

Just to emphasize - not done by me! That model went straight from its previous owner to your hands (though I suspect the damage may have been done by a particular centre of modification, in its renaming/numbering, and not by the previous owner).

It's looking really good Graeme. How much would need to be done at this point to turn the A2 into the A2/2 variant? Not much I'll wager...?

If thats the loco I think you a referring to then yes, you would be right, no mods by me...but was done by who I had used to renumber....hmmm sorry about that, I hadn't noticed as long as it doesn't detract from the beast it now is