Airfix 14xx tank Loco

[cessfordalan]

Good Afternoon Everybody,

I have two Airfix Auto tank Locos of which one runs extremely well and the other one does not. The problem with the non runner is the pick up plunger on the the right hand side of the radial wheels[ looking from the bunker end]is not connecting with the back of the wheel, it can be eased out with a fine screwdriver to the wheel but moves back again when the loco moves around a bend. Looking at the running model there appears to nothing missing or is there a  thing? supposed to be keeping it in place. Alternatively has anyone fitted an extra pick up as I cannot remove the keeper plate to see the radial axle wheels. any advice would be appreciated as both these models have sentimental value and I would like to see them both running

 

Regards 

Alan Cessford      

[Butler Henderson]

The problem is the springs in the plungers cannot cope with the max current that the motor can draw so fail. One solution is to permanently couple the loco to an autotrailer fitted with pick ups to its wheels. The 14xx can easily be altered to a wired connections to the motor by swopping the brush holders round with w]the wires added to them ; the one that fits downward normally fitting upwards into the dome.

[sandwich station]

I bought 2 of these many years ago second hand, one has the original plungers but the other has been converted to wipers. Although I haven't run either for quite a few years, I seem to remember the wiper pickups worked extremely well.

[DCB]

The plunger springs can't take the current of a dead short, if you have live frog points then run it into a wrongly set point and you fry a plunger spring.   These locos are 40 years old now.  I changed one of mine to phosper bronze strip pickups and scrapped the others when I ran out of servicable plunger pickups. the drag on the rear axle is a big issue when using strip pickups.  Some people will tell you a Comet chassis is the answer, I found an ancient  brass chassis with a Triang XT60 motor intended for a K's 14XX for one of mine which made a vast improvement.   The K's and similar chassis with pivoting trailing trucks are hopeless. My plans for a 6 wheel drive final solution continue apace.

[Gricerdon]

My Airfix GWR Auto tank was shorting out having run well for years, though not extensively used.

 

I dismantled it and cleaned everything. Now it isnt shorting but wont run at all. Any ideas?

[33C]

Are the plunger pick-ups making contact with the wheels? Have you made sure the copper contact on the motor/chassis, is fully slotted in? Is the central contact through the chassis making proper contact? Did you ensure the cardan shaft is attached to the worm/motor? 🤓

[Gricerdon]

Ok thanks.I will work through that list

[Gricerdon]

Tried all that and it all seems to be Ok but no luck. Any other ideas? How can I check if motor is working?

[33C]

9 minutes ago, Gricerdon said:

Tried all that and it all seems to be Ok but no luck. Any other ideas? How can I check if motor is working?

Are the brushes there? Connect them direct to the controller and make sure one is insulated from the other, like the Hornby X04. If it runs, then the problem lies in the collection from rail to wheel to motor, somewhere in the circuit. 

[DCB]

11 hours ago, Gricerdon said:

Tried all that and it all seems to be Ok but no luck. Any other ideas? How can I check if motor is working?

Is the spring which fits over the long brush holder on the motor and bears on the copper pick up strip present?   Its easy to mislay. The plunger pickups stick, are they free?  If so are they fitted so they bear on the wheel backs, they need to be positioned carefully to work,   Be careful if you remove the top chassis casting, if its not down properly and you tighten the screw the chassis snaps above the leading axle and the gears strip.   Check the motor by taking it out and putting a wire to each brush holder or AFAIR the long brush holder to one rail and the motor frame (with the top brass contact fitted to the short brush holder and motor frame) to the other rail and apply power.  Motors are generally bullet proof and useless, too heavy and don't fit anything else.

I have had about 8 of the things, They ran beautifully from new then pick ups started failing, now none are running.  Nor do my Dapol or Hornby ones. My latest is having a K's chassis with Triang XT 60 motor fitted, and behind it in the queue an Airfix with strip pickups and a tiny computer motor instead of the huge Airfix lump, it only needs to pull 5 coaches on my layout, not the Flying Scotsman.  I only remembered this long forgotten project when I read this thread.   It needs a 6wd chassis with powered rear axle, not rocket science different gear ratio on the rear axle? 

[melmerby]

I've got two of these, both with original plungers and they work fine.

The problem I found is the plungers get gunked up with the original grease which eventually stops the springs working properly

If propely degreased they function perfectly well and mine haven't had any problems with damage caused by two much current.

If current was going to damage them, it would have done so by now.

Both have been dcc'ed and neither has traction tyres, meaning they pick up on all wheels, not just 4 as with the tyres.

[DCB]

18 hours ago, melmerby said:

I've got two of these, both with original plungers and they work fine.

The problem I found is the plungers get gunked up with the original grease which eventually stops the springs working properly

If propely degreased they function perfectly well and mine haven't had any problems with damage caused by two much current.

If current was going to damage them, it would have done so by now.

Both have been dcc'ed and neither has traction tyres, meaning they pick up on all wheels, not just 4 as with the tyres.

It's live frog points which kill the plungers, as you approach the heel of a wrongly set point there is an isolator between a positive rail and a negative rail, when the first wheel crosses the isolator the current path is first wheel, - chassis - second  wheel on the same sides putting a dead short across both plungers.  That causes the plunger spring to heat and fail. The problem doesn't occur with dead frogs.

Did you swap the grooved wheels for non grooved?  I swapped mine, I think I swapped the metal tyres rather than the whole wheels but I might be getting mixed up with the 2-6-2T where I definitely swap just the tyre. 

Edited May 13, 2022 by DCB

[melmerby]

Both are DCC'd

I've got all live frog pointwork and I've driven them into wrongly set points, the system trips in milliseconds so little chance of heating in that time

 

I've kept both pairs of solid wheels and put them on one 14XX, the other one has new Gibson wheels.

Cuts down on haulage, but no real problem on just Loco + Autotrailer.

 

They are original Airfix and are rather knocked about now, I bought both second hand a long long time ago and the plungers didn't work properly because of the solidified grease.

A good clean and they have been fine since.

[Stephen Freeman]

I have never been a fan of plunger pickups in any scale, the best ones I have seen (not for a while) were DJB in 7mm scale. With the Airfix 0-4-2T, change the pickups for new plungers (if that's possible), the other worthwhile alteration to the chassis is to get rid of the tyred wheels and have all metal, haulage will be perfectly adequate. The best solution of course is to ditch the chassis and build a replacement- plenty of etched brass alternatives around.

 

Bodywise, Iain Rice did a detailing pack, which was taken up by Mainly Trains and I believe is now with Wizard Models. How far you take it is a matter of personal preference.

[DCB]

1 hour ago, melmerby said:

Both are DCC'd

I've got all live frog pointwork and I've driven them into wrongly set points, the system trips in milliseconds so little chance of heating in that time

Mine are DC and the trips re set automatically, if they trip at all.   My dead plungers are very free to move loose in fact but when I get hem apart the springs have collapsed to brown crud.  

 

1 hour ago, melmerby said:

I've kept both pairs of solid wheels and put them on one 14XX, the other one has new Gibson wheels.

Cuts down on haulage, but no real problem on just Loco + Autotrailer.

I have  happy memories of a 14XX getting away from Winchcomb on the climb towards Greet (?) tunnel on the GW(S)R with at least 5 if not 6 Mk1s without a hint of a slip.  Later a 9F with a similar load lost her feet quite spectacularly...  Gloucestershire 14XX could manage 5Mk1s up I in 150 and back in the 1950s were timed at  80MPH on the flat with 2 X Autotrailers between Gloucester and Standish Junction..

1 hour ago, Stephen Freeman said:

Bodywise, Iain Rice did a detailing pack, which was taken up by Mainly Trains and I believe is now with Wizard Models. How far you take it is a matter of personal preference.

A lot of models have detailing packs but don't address what for me are the glaring errors of the undersize smokebox door and the cab roof join in the wrong place.  The Full size 14XX cab sides wrap over above the cab cut out and join the roof some inches or so inboard of the cabsides.   The Airfix/Dapol/Hornby has slightly overhanging eaves which scream "Wrong" to me.

The smokebox door is a standard GWR part, that's why some, like 14XX and 45XX look like the door is too big and others with std 4 and std 1 boilers (Hall etc) look like they are too small.  Luckily the aesthetic considerations over ruled the bean counters or the Kings and Castles could have looked main queer with a Hall smokebox door. 

 

 

[melmerby]

On 12/05/2022 at 08:23, DCB said:

   It needs a 6wd chassis with powered rear axle, not rocket science different gear ratio on the rear axle? 

Ratio 44 : 62 (or 22:31) between the drivers and trailing wheels.

I considered it for a replacement chassis for the deadful K's one, but suitable gears were not forthcoming when I looked.

[Barclay]

On 13/05/2022 at 11:10, DCB said:

Mine are DC and the trips re set automatically, if they trip at all.   My dead plungers are very free to move loose in fact but when I get hem apart the springs have collapsed to brown crud.  

 

I have  happy memories of a 14XX getting away from Winchcomb on the climb towards Greet (?) tunnel on the GW(S)R with at least 5 if not 6 Mk1s without a hint of a slip.  Later a 9F with a similar load lost her feet quite spectacularly...  Gloucestershire 14XX could manage 5Mk1s up I in 150 and back in the 1950s were timed at  80MPH on the flat with 2 X Autotrailers between Gloucester and Standish Junction..

A lot of models have detailing packs but don't address what for me are the glaring errors of the undersize smokebox door and the cab roof join in the wrong place.  The Full size 14XX cab sides wrap over above the cab cut out and join the roof some inches or so inboard of the cabsides.   The Airfix/Dapol/Hornby has slightly overhanging eaves which scream "Wrong" to me.

The smokebox door is a standard GWR part, that's why some, like 14XX and 45XX look like the door is too big and others with std 4 and std 1 boilers (Hall etc) look like they are too small.  Luckily the aesthetic considerations over ruled the bean counters or the Kings and Castles could have looked main queer with a Hall smokebox door. 

 

 

The Wizard/Mainly Trains pack includes a new smokebox door.

[LimboBrit]

I acquired one of these recently and have also invested in the Wizard detailing kit which I still need to get around to fitting. I also want to fit a DCC decoder. Does anybody have any recommendations about which decoder would fit and how to fit it?

[Butler Henderson]

Its very simple to break the pick up to motor connection by swopping the brush contacts around - the lower one with the long metal prong fits upwards into dome. As for an appropriate decoder you need to a stall test of current drawn which will be quite a lot given the motor used and ensure you get a decoder appropraitely rated.

[melmerby]

The two I have with DCC decoders use a DN135 (Digitrax) and a TCS M1. both are 1A rated with the DN135 at 1.25 peak and the M1 at 2A peak.

I use those because they were replaced by better decoders (Lenz) in other locos.