Thomas Telford Locomotive - Take Two

[Chris Cairns]

Mamod lubricators still suffer from design problems. Unlike the inline lubricators as used by Cheddar Models/IP Eng/PPS/Dream Steam/Roundhouse/etc. where the steam pipe goes straight through the lubricator, but either has a small hole (smaller than the internal diameter of the pipe) or a graduated valve, the Mamod one fitted to the Mark II & Brunel locos has the steam pipe going into lubricator body, and either an overflow style exit steam pipe (Mark II) or a steam hole through to the valve block (Brunel). So these lubricators displace all of their steam oil a lot quicker.

On my Brunel despite having steam pressure my loco will slow down due to 'stiffness' during a run. I then need to refill the lubricator. It also suffers from the condensate escaping through the piston gland (which is at the bottom) and washing out the lubrication on the drive shaft - I have fitted more packing to the gland to reduce the effect of this leak.

Compared to my Cheddar Models & Bix ceramic gas burners I find the material used by Mamod can cause the flame patterns to stray due to external influences (exhaust steam dropped onto the track bed from the William, William II & Mark I locos, or the close proximity of the chassis on the Brunel). The material on my Brunel burner is sealed in with heat gasket compound by Mamod, and I now include that in my plan to replace those nylon gas pipes with copper pipe (just done my William II and the burner works better now).

The Garden Railway community are still going to be very critical of a filler plug sticking out the RHS of the cab bodywork.

Mamod do listen to suggested improvements and criticism of their products, but can take some time to react. For example the use of a nylon gas pipe has been criticised for years (I recorded their use in my YouTube videos), and following a spell of only when requested by the customer, they are now fitted with a copper gas pipe as standard. On the other hand after the Garden Rail magazine review of the pre-production Brunel the Garden Railway community criticised the position of the boiler sight glass and the lack of an extra boiler outlet. A new design sight glass was fitted further inboard and a blank boiler outlet included from the 2nd production batch. They have subsequently improved the method used to fix the axles into the chassis (no more 'O' rings).

Interesting that you had a 'wobbly' wheel on the Brunel as the wheels are securely screwed to the axle. Was the problem actually the cast cranks on the axle as I know someone else had problems with these, and when I re-gauged mine to 45mm to run on our railway group's indoor garden railway I had to redress a couple of the castings to make them fitted properly?

I know that Mamod are members of the Unofficial Mamod & Freesteam forums, but not sure if they visit this Forum.

I intend writing to David & Peter suggesting some of the observations from here, and looking into the possibility of a kit build Thomas Telford. However as they have committed to building 21 locos already I may have quite a wait.

Chris Cairns.

[dougrail]

I would advise contact and highlight this forum's existance too. Your enhanced perspective would be an asset, Chris in my eyes.

[mikewakefielduk@btinterne]

It seemed as though the wobble was caused by the wheel's hole being drilled not quite at 90 degrees to the axle although, to be honest, I didn't look too carefully. More interestingly, it took Peter two goes to find a replacement wheel set that didn't wobble as well.

As for lubricator designs, I suspect Mamod are aware theirs has its faults, hence the proposed change from TT 21 onwards. Of course, if they simply keep the same design but with an added drain cock and larger capacity it will still use the oil up at the start of a run.

Regarding suggestions to improve the Brunel, would it be worth opening another thread on the forum so members could post their adaptations or simply add them to the existing Brunel Vertical Boiler thread?

Mike

[Chris Cairns]

Mike,

It is up to you whether you wish to start a new Topic or add to the current one, as we only have 3 Brunel owners I believe.

For me the advantage of adding to the same topic is it is easier to find again - the Search facility provide by MyFreeForum could be a lot better (you can get better results using a Google specific forum search).

Chris Cairns.

[steamie1]

When you look at old photos away from the slate mines, to munitions factories, docks and obscure Narrow gauge lines. This Telford, carries a new fresh look in the 16mm scene which I'm sure I have seen in an old black and white shot somewhere. A bit of cab detail, say all black heavily weathered no brass showing, it could be a niche look. If the burner arrangement is the same as my Mk2 it should be good.( I can't stop loving the new Mk2 sorry) I do hope the running is good, as I think it will go down well if it is. I like the look.

[dougrail]

I imagine my hypothetical future TT in Middle Chrome Green with umber and black lining, with cylinder covers in black, and shining brass...

[mikewakefielduk@btinterne]

Anyone know of the car paint colour the corresponds to Mamod Green?

[Chris Cairns]

As Doug said in his original posting this loco reminded him of a Lynton & Barnstable one.

I agree, despite the different proportions and wheel arrangement, the bodywork looks to be inspired by the Manning Wardle locos. So a variation of the Southern Railway paint scheme would work well.

I've sent my letter to Mamod so I'll keep you updated with any feedback from them.

Chris Cairns.

[Sir Clothem Cap]

I am impressed with the mamod improvements, they must have listened to comments to get this far. I'm not overly worried by the cab cut out as if it helps in operating the controls better its worthwhile.

[Spule 4]

4. Slots in the Cab back. Doug had mentioned these in his previous posting. What is their purpose?

Chris Cairns.

I wonder if we will be seeing a "drop in" rear bunker/back sheet for the cab. One that can be pulled "up and out".

[mikewakefielduk@btinterne]

A rear bunker would be a good place to hide any R/C gear. You'd only be able to control the regulator but would be better than nothing.

[mikewakefielduk@btinterne]

According to Mamod the dimensions of the TT are:

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

I don't have a MkII to hand to measure these dimensions against but my Ragleth measures:

length: 13.5" (340mm) - but that's including the chopper couplings
width: 4.625" (120mm)
height: 6.5" (165mm)

So the TT looks like fitting in pretty well with other 0-4-0s in the Garden Rail community.

I also asked how the steam testing was going. Apparently pretty well - they're just waiting for some slightly smaller o-rings to tweak the slow running.

[dougrail]

Awesome little update there Mike, thanks for letting us know. Sounds like there are orings in le pistons then...

[Chris Cairns]

We already know it is much larger than the Mark II. The William II measurements are: -

Length: 9 & 3/4".
Width: 4".
Height: 5 & 1/2"

Sounds like there are 'O' rings on the pistons then...

Not necessarily so. To date Mamod have not fitted 'O' rings to any of their pistons whether oscillating or sliding valve, and they have not mentioned fitting them in any of the Thomas Telford publicity. Would be a very welcome bonus if they have.

Could easily be the small 'O' ring which seals the piston rod inside the gland. On my Brunel with the cylinder pointing down there is a significant leak of condensate through the gland, so I have had to add extra packing to reduce it.

Or it could be the 'O' ring on the regulator.

You'd only be able to control the regulator but would be better than nothing.

Given that they are fitting a fine thread regulator then putting R/C on that will be a challenge, probably needing some form of gearing and possibly using an adapted sailing winch servo.

Chris Cairns.

[steamie1]

8 long by 5 high by 3 wide Inches Mk2 for comparison

[Chris Cairns]

Some useful feedback from Peter Johnston at Mamod with reference to the Thomas Telford (text in Red) from my recent letter.

1. Smoke box apron/front footplate. The cut-outs just behind the buffer beam are generally disliked. As many owners would be adding smoke box castings, and would like to add things like sand boxes, tool boxes, re-railing jacks, etc. then extending the apron/front footplate to the front of the side tanks would be a simple but great improvement. Mamod - This could be done easily however the first forty foot plates have already been cut, also it will make assy harder, but not impossible.

2. Combustion Chamber. (edited version) I trust the Thomas Telford combustion chamber will be the same semi-hexagonal construction. Mamod - The Telford will use the same baffle as the Mk2.

3. Gas Tank Position. As you found on the initial release of the Brunel locomotive the Garden Railway community does not like anything sticking out the side of a locomotive if possible. By extending the gas pipe it would be possible to mount the gas tank with the operating valve facing backwards and being accessed through the cab rear. Of course that would require the access hole in the cab roof for filling being made in a new position. Mamod - This is more of a problem as we try to use standard parts where possible but we will look at it if proves to be a problem.

4. Lubricator. (edited version) I understand that there is already a design change on the way from Loco No.21 onwards, with the first 20 using the current Mark II lubricator. First problem is the large filler plug sticking out the right side of the cab is disliked. I appreciate this is to make it easier to fill and drain the lubricator but to keep the smooth lines of the loco could the filler plug not be mounted on the top or rear face of the lubricator block, allowing the use of a syringe for filling and draining (I understand one of the above changes may be a separate drain plug on the bottom). Mamod - I have had an image emailed to you so you can see the new lub with a drain cock. The filler would be better located in the cab, but the production of 200 have been made. Next time maybe.



5. Cab Roof. I assume that the rear of the cab roof has been cut-out to allow better access to the regulator. I believe this is not prototypical of the full size locomotives, and see no real problems accessing the regulator with a full length cab roof. Mamod - We have had favourable comments about the cut out?

6. One question – is there a specific purpose to the 4 slots cut into the cab back? Mamod - The slots are for a back probably a coal scuttle back.

7. A Kit Build Locomotive. (edited version) I understand that this is being considered and I feel that the Thomas Telford locomotive would be the ideal candidate. One thing to clear up is how the side tank panel is currently attached to the cab? Mamod - as to a kit I'm sure David would be willing to sell a unassembled model if you are interested. The side panel is currently held in place by spot welds and the forward hand rails.

Mamod - Once again thanks for your valuable input and any further comments you can think of we would appreciate.

Chris Cairns.

[steamie1]

Firstly the effort Chris has gone to and the help and advice must be commended. Thank you Chris.
On cosmetics the angled roof and cut out just add a fresh difference which is much needed in the freelance locos. The gas tap one side is easier to grab on a pass than most in cab jobs needing tilt up roofs etc. I can grab my Mk2 on the go and turn it down a smidge, better than Charles or Tom rolt or even Ragleth. Lubricator outside filler knob is not that good in looks for me, but when painted tend to reduce in visability. What I do think is really important is :-No wobbly wheels (all pre tested) and it has to run well. It has to run well to contend Roundhouse and Accucraft. Adjusting cosmetics to suit ones line is fun and all we need is a good freelance loco. Perhaps the Mamod side tank stickers could be left in the box unstuck as a cutomer option. We might like to put them on the plinth or carry box. The chassis cut out is a bit slim round the smoke box for me too. A lever type regulator handle is easy to see where it is and adjust on the move quickly. Hard steel coupling rods and tapered hard steel wheels might be nice, things like the latter add durability, which is a long term seller. In conclusion running is everything in the 16mm scene. If it runs bad it would be better to stick with oscillators for Mamod as a company. I do hope in the running.

[Chris Cairns]

Some useful feedback Lloyd.

1. Gas Tank Valve. Most of my experience is limited to indoors running so there is less requirement to adjust the gas once set for running, but I can see your advantage of adjusting on the fly whilst running outdoors in windy conditions. However on the early runs with my Mark I loco I suffered a major runaway derailment which dented the bodywork and bent the gas tank valve knob on the shaft.

2. Lubricator. With production starting before the prototype has finished its running trials we are now committed to 220 lubricators with the filler plug sticking out the side (20 of the Mark II style, plus 200 of the revised design). So it will probably be a couple of years before that situation changes.

3. Wheels. The wheels fitted to your Mark II are diecast Mazak which Mamod have made externally. Although the pressing method used is much improved on the old Mamod SL/MSS ones we have had the 1st loose wheel suffered by John Rogers on the Mark I which was reviewed by Garden Rail, and subsequently bodged by John. Loctite 603 has fixed his problem. The wheels on the Thomas Telford are the same as the William II ones which are machined steel. These have a similar rim profile as the Mark II ones which allow the loco to run on Hornby 'O' gauge or Bowman track as long as you keep the speed down, although I have difficulty getting them to run properly on my John Prescott rolling road.

4. Side Tank Plaque. Leaving these loose in the box allowing the customer the option of fitting them or not is a great idea. When I got my Mamod Tender for the Mark I loco that was how it came and I recall saying to Mamod that that was a great idea. I'll put that recommendation to Peter Johnston in my e-mail reply.

5. Regulator lever. Would be a nice addition but currently not used by Mamod on any of their products, so one for the after market traders. Interestingly the design used by IP Eng on their Janes is prone to working loose - I have 2 and it is difficult to get the lever glued/soldered back into the collar properly. A threaded lever into a suitable collar would be best.

PS - I had not noticed till I looked again at your last Mark II image that you have already modified your regulator with a lever and filled down your gas valve control.

Chris Cairns.

[mikewakefielduk@btinterne]

I agree that a regulator handle could make a lot of difference. I've just fitted a spare Accucraft regulator handle to my Brunel and its made it much easier to control so this will be one of the first changes I'll make to the TT when it eventually arrives. (It will also make it easier to attach a R/C linkage if I ever go down that route.)

The original Mamod regulator wheel on my Brunel was attached with an internal 6BA thread which was then soft soldered. Presumably they'll attach the TT one in the same way so perhaps we could ask them not to solder it, so making it easier to remove?

Mike

[mikewakefielduk@btinterne]

I received a text from an acquaintance this morning to say he'd contacted Mamod re the availability of the TT and been told it was likely to be at least February or March next year. I then gave Mamod a call to see whether TT no. 21, which had been promised for February, was likely to be delayed. Seems they're having an issue with the loco under steam – it starts off fine but after a small while begins to run very slowly. They think the issue remains with the piston O ring, and Mamod are having difficulty sourcing one of the correct size. The one fitted at the moment is too big apparently.

I thought they hadn't fitted O rings to their pistons up to now but was assured they did to all non-oscillators.

So I checked by removing the cylinder of my Brunel and had a look and what they say is correct. Although I haven't yet figured out how to remove the piston itself if you look carefully through the cylinder face bottom steam hole you can make out an O ring at the bottom of the piston's stroke.

Presumably if they can't source the right size O ring the only alternative is to make the cylinder diameter a fraction larger?

Mike