Thomas Telford Locomotive - Take Two

[mikewakefielduk@btinterne]

I've just got my PC working again after a disk crash and discovering none of the backups this side of February 2012 were readable. Any emails received since then, including the detailed ones from Chris, have unfortunately been lost.

Anyway, am now back on line and have been reading the news section of the Mamod web site. Apparently its going to be the year of the Telford, so that's something to finally look out for. Mind you the same article also said the Telford was an updated version of the Diamond Jubilee saddle tank, which is not quite how I see it. Surely an updated William would be nearer the mark?

Mamod are going to be at both the Midlands garden Rail Show in mid March and the 16mmngm Show at the beginning of April, so presumably they'll have the Telford ready in time.

Mike

[dougrail]

THOMAS TELFORD LOCOMOTIVE UPDATE 15-01-15

1) Chimney



At Warley, looking at photos, the brass fitting was a conical/diamond shape downwardly pushed into the chimney. As seen here, this was artfully curved, made to be more flush with the actual stack and louvered on top for a more pleasing look.



2)Cab



Cab back has now been developed. The sliding roof has also been designed and built to prototype level. Think old-school Accucraft.



Inside the cab is a new shot of the new inline lubricator. The gas tank is made from brass and pressure tested [NOT plastic as many thought]. The regulator has been fine tuned to try and get a good run and control. The red knob is also Accy style as seen - but nothing stopping a customiser from adding a proper regulator handle should they want....


The regulator has been developed to make for a well-controlled loco. I'm told a quarter to half a turn will get the loco running and although the boiler is 40-50psi, it will run on 12-18psi quite well.

3)Frame construction
The loco which was seen at Warley was a prototype - NOT a final model. Another prototype is being build - see the cab. First photo shows the next model - its fold/construction is much tighter than the Nov 14 model.





Also, bufferbeams are being redesigned. They will finish bottom end flush with the black footplate/frame now and will be a 'T' shape - think like Edrig etc. The side holes will be riveted - but the main coupler will remain a nut/bolt to enable changability should an owner which to change coupling types.



The following photo also shows the steam system on the Nov 14 prototype.




4)Dimensions


First off - as many have wondered - comparison with a Mamod 1989 SL6. Longer than SL, wider than SL. Slightly taller.



The boiler will be 44mm diameter. The wheels - some people commented about how they seemed undersize. Bearing this in mind I was allowed to measure up. A Mamod SL wheel is 32mm diameter. The Telford wheels are 36mm. Also, new conrods are being made - the tiny little details that can make a difference.



5)Changes
Finally managed to establish, "word of God", why the extremely attractive "2012" 'Lynton-Barnstable look-a-like' body was changed. Photos see how the width was reduced on the two body designs.



It seems that the loco was somewhat topheavy and the centre of gravity was enough to make it keel over at speed on curves. The centre of gravity to do this was also why the footplate is recessed between the bufferbeams and cab which is a shame. Mamod reckon for a 45mm gauge loco it'd be fine but for 32mm it's teetering.



The lengthways centre of gravity is also why the wheels are not 'dead centre' in the length of the chassis. The boiler is a full steam vessel from end to end. When full, where the wheels are the weight is spread just about equally on both axles.

6)New Material
A separate model of tender is being built for the Telford range.



New frames are being designed for the locomotive as per the photo. These will be at least double the thickness of the old SL frames and thicker than Nov 14's prototype. This will add rigidity and weight to the loco. They also will be straight edged, no diagonal in them at the front.



7)Addendum
Mamod are keeping the whistle fitting, but are removing the lamp that has been on incarnations upto Nov 14. I suggested fitting lamp irons - it would allow further personal choice and add another edge towards making the locomotive more attractive to the garden railway set.

Mamod have also considered doing a batch in black as well as the customary green which could well be popular.

Looking promising, especially with the video released a few weeks ago.

[mikewakefielduk@btinterne]

Fingers crossed it all works well. I've already made a replacement steam regulator which should be far more sensitive so allowing me to fit a radio control servo with just 90 degrees of movement.

I had been hoping the back of the cab would be designed as coal bunker (think Accucraft Ragleth) but no worries. If I can't find anywhere else for the battery pack it can go in the new tender.

[bessytractor]

anyone else noticed the smokebox door is a Roundhouse Millie door?

[Chris Cairns]

anyone else noticed the smoke box door is a Roundhouse Millie door?

Only if Roundhouse get theirs supplied by Steam4Fun, as Mamod does.

Chris Cairns

[DLRdan]

I would think Steam4fun get the door from Roundhouse, along with some other things.

[Chris Cairns]

Certainly possible Dan.

Comparing my oscillating Thomas Telford smoke box door with an old Millie smoke box & door in my bits box, the Roundhouse one is a sharper casting.

So could be just that the quality of castings has dropped slightly, the mould is showing its age, or Simon has made his own moulds from the Roundhouse originals. Had the impression that he did or had his own castings made.

Difficult to see any real differences in the traverser jack castings between Roundhouse & Steam4Fun.

Chris Cairns

[mikewakefielduk@btinterne]

I take back what I said previously about the Telford being on the small side. If you've read the chatter on the 16mmngm group about the new Accucraft Decauville 0-4-0 and then read up on the details, especially the dimensions, the Telford isn't too small at all to appeal to the Garden Rail community.

Now I don't know the exact dimensions of the Telford when Mamod finally launch it but the original Telford's dimensions were:

length: 11" (280mm)
width: 4.625" (120mm)
height: 5.5" (140mm)

and the dimensions of the new Accucraft Decauville are:
length: 8" (213.5mm) excluding buffers, 265mm with buffers
width: 3.5" (89.7mm)
height: 5.375" (138.3mm)

Mike

[Boustrophedon]

What's the working pressure of the boiler on the Telford.

[mikewakefielduk@btinterne]

40 psi

[Boustrophedon]

I won't be buying one if it has a plastic sight glass then.

[mikewakefielduk@btinterne]

Here's the Telford finally tamed to run around the challenging loop part of my garden line (gradients and tight curves) without any manual intervention.

https://www.youtube.com/watch?v=hWu5sw-URyw

I cobbled together an inertia flywheel device made from a Zecar toy from Amazon fitted with Accucraft wagon wheels. It holds the Telford back when it wants to race away downhill and gives it a shove when it wants to stall coming uphill.

I think the Telford is currently a little underpowered for tracks like mine that aren't dead level but I understand Mamod are looking at this and considering larger cylinders. Some of you may recollect the early Accucraft Ruby had exactly the same problem and was transformed when 1/2 inch cylinders were fitted in place of the original 3/8 inch. (There was at least one other Accucraft model that was also later fitted with larger cylinders - was it the Excelsior?)

As for plastic sight glasses, I've never had a problem with them.