Hornby Railroad D49

[60800]

Bachmann are indeed about to produce a 2251 with a GC tender

Could anyone point me towards some info on this loco / class please? My search has come up fruitless

[S.A.C. Martin]

Bachmann are indeed about to produce a 2251 with a GC tender

Could anyone point me towards some info on this loco / class please? My search has come up fruitless

It's literally just a 2251 locomotive with a ROD tender. Tender swaps happened quite often.

On the Bachmann site here.

2251 Wiki entry found here.

Google is your friend

[Atlantic 3279]

Back to the D49 theme: I said a little earlier "If I have time, and if I can find any pictures, I may later post up an indication of what I did and how far I got. It included adding stepped copings to the tender."

If it's of interest, I've posted pictures here:
viewtopic.php?f=3&t=6672&p=57265#p57265

[S.A.C. Martin]

Really nice mods there Graeme, particularly the cylinders. Is the latest schools chassis a match, more or less, then, with the D49?

[Atlantic 3279]

The coupled wheelbase is fine but the cylinders may need nudging back a touch. A major nuisance is that the motor and bracket will foul the inside of the firebox badly at the rear, requiring some cutting out and re-instatement. I may look first of all at the question of whether I can substitute A4 coupled wheels to get the right sort of balance weights, rim profiles, and all metal tyres. The bogie is no use at it is - much too long.

[Atlantic 3279]

The new mechanism runs well enough - a bit hard to get used to the way it responds very suddenly to the controller (compared to modern models), and the traction tyres create the usual problems, but otherwise it's ok, about as good as the old tender-drive one!

Looking again at your pictures I've just been prompted to comment on this. I'm impressed to see that a flywheel of sorts (albeit minimal thickness and mass) appears to have been worked in to the drive train between the motor and the worm. Unfortunately, unless there's some double reduction going on out of sight, the cause of the loco being a bit quick to respond to the controller is quite evident - look how coarse the pitch is on that worm gear! I'd be surprised too if Hornby have gone for the most exotic breed of slow-revving, high cost, high quality can-motors.
I want a definite improvement over the best I could do by tweaking my Ringfield tender drive unit, so I hope this may point to my choice of a "super detail" Schools mechanism as being a good one.

[Coboman]

I want a definite improvement over the best I could do by tweaking my Ringfield tender drive unit, so I hope this may point to my choice of a "super detail" Schools mechanism as being a good one.

What improvements did you make to the ringfield? I fitted a Romford 2mm tophat bearing that had been reamed out to 2.4mm into the plastic end plate of the motor, screwed that to the motor body instead of those plastic clips, used model filler to fill in the gaps on the armature and smoothed it all flat, bought a huge bag of the drive cogs and selected the ones that were a tight fit (the variation in the hole diameter was quite alarming!), and finally spaced the axles out with romford thrust washers (not sure on that terminology!) so there was no play. After hours of running in they ran very smoothly and virtually silently, but you can never get rid of the cogging without a feedback controller. All this was performed years ago when there was no other option than to scratchbuild a chassis (way beyond my abilities).
Jim

[Atlantic 3279]

Hi Jim,

You did a lot more than I did! I too spaced out the wheelsets to eliminate the side-play, an essential move merely to keep the gears in mesh after I had opened up the back-to-backs to 14.5mm. Beyond careful lubrication, my only actual "alteration" to the motor unit concerned the rubbery ring magnet. Bought "used", untried, when I first ran the loco I was hugely disappointed at just how "coggy" it was compared to my B17 with "identical" drive unit. It was however surprisingly fast and powerful. I spent a long time search for signs of differences in gearing, armatures, state of lubrication etc, and found nothing. I then noticed that the split in the ring magnet, and the gap bewteen magnet and armature on the D49 unit looked tighter than those in the B17 version. I could also see hints of some sort of shiny layer between the outside of the D49 magnet and its housing. On stripping out, I found that either the factory, or (more likely I thought) a previous owner had wrapped a layer of shim metal around the magnet to tighten its fit and "boost" the inner magnetic field. On removing the shim and placing a little packing in the ring-split to keep the magnet tightly back against its outer housing, the unit performed much more like that in the B17 - less coggy, smoother and slower starts /stops, and still more than enough power for the job. I don't know if/why somebody had felt that extra power was needed at the expense of smoothness.

I considered building a new powered chassis too, for the tender for simplicity, but dismissed the idea not on grounds of difficulty but on grounds of cost. By then, Markits had substantially whacked up their prices for wheels, axles gears etc (two or more sets of gears for a tender drive), metal alone for the frames was rising in cost as too were decent motors. The same cost consideration ruled out the superficially attractive idea of a ready made Bull Ant unit. Incidentally, when a mate of mine ordered such a unit for a Sentinel kit, specified 60:1 reduction, waited for manufacture / delivery, and received instead initially a 15:1 unit I was relieved that I hadn't bothered.....

[S.A.C. Martin]

D49 Conversion

Link to my thread. Hopefully of some use to whatever other nutter decides he wants a one-off Thompson machine...!

[Coboman]

Hi Jim,

You did a lot more than I did! I too spaced out the wheelsets to eliminate the side-play, an essential move merely to keep the gears in mesh after I had opened up the back-to-backs to 14.5mm. Beyond careful lubrication, my only actual "alteration" to the motor unit concerned the rubbery ring magnet. Bought "used", untried, when I first ran the loco I was hugely disappointed at just how "coggy" it was compared to my B17 with "identical" drive unit. It was however surprisingly fast and powerful. I spent a long time search for signs of differences in gearing, armatures, state of lubrication etc, and found nothing. I then noticed that the split in the ring magnet, and the gap bewteen magnet and armature on the D49 unit looked tighter than those in the B17 version. I could also see hints of some sort of shiny layer between the outside of the D49 magnet and its housing. On stripping out, I found that either the factory, or (more likely I thought) a previous owner had wrapped a layer of shim metal around the magnet to tighten its fit and "boost" the inner magnetic field. On removing the shim and placing a little packing in the ring-split to keep the magnet tightly back against its outer housing, the unit performed much more like that in the B17 - less coggy, smoother and slower starts /stops, and still more than enough power for the job. I don't know if/why somebody had felt that extra power was needed at the expense of smoothness.

I considered building a new powered chassis too, for the tender for simplicity, but dismissed the idea not on grounds of difficulty but on grounds of cost. By then, Markits had substantially whacked up their prices for wheels, axles gears etc (two or more sets of gears for a tender drive), metal alone for the frames was rising in cost as too were decent motors. The same cost consideration ruled out the superficially attractive idea of a ready made Bull Ant unit. Incidentally, when a mate of mine ordered such a unit for a Sentinel kit, specified 60:1 reduction, waited for manufacture / delivery, and received instead initially a 15:1 unit I was relieved that I hadn't bothered.....

Thanks for that, very interesting. Re wheeling and re gearing stuff is an expensive game now....

[S.A.C. Martin]

A couple of images to chew on - my unrestored D11 bodyshell I bought many moons ago, sitting on top of the Hornby ex-D49 chassis. I suspect a second D49 may be bought this year to put the bodyshell to good use.





Obviously a lot of work needed on the D11, and the D49 chassis, along with a new GCR tender, but I suspect the result would be a rather decent running chassis with all that whitemetal weight on top. Your thoughts as always, appreciated gents.

[Atlantic 3279]

That's interesting Simon. How is it for fore-aft balance? My Little Engines whitemetal D11 was so nearly nose-heavy that I thought it best to hack the chassis around to make it ride on the bogie at the front (and to have completely compensated coupled wheels at the same time, aiding traction and pick-up so vital in a 4-4-0). Making the chassis ride on the bogie gives another good result - you can have large GC bogie wheels and minimal frame cut-outs, safe in the knowledge that the frames and running plate can never sit-down onto the tops of the wheels. Even with the bogie carrying load to balance the loco, I still found however that for serious pulling power on metal-tyred wheels I had to load the weight of the front of the w/m tender onto the rear of the loco.

[S.A.C. Martin]

No doubt in my mind Graeme that the front bogie would need major alteration as the bodyshell is extremely nose heavy.

The whole bodyshell would need major alteration to be frank, in order to fit properly at both ends, but I feel the potential for this chassis to be put to good use for different classes is high, particularly in this case.

My bodyshell didn't have any form of cab interior, due to the type of chassis it was using (Triang/Hornby L1 4-4-0 chassis I think?), so that may be stumbling block for me later on!

The size of the axles on this D49 chassis are different to the original D49 chassis, so like for like wheelset replacements isn't possible unless you use after-market ones like Romfords or similar. I think it's been said elsewhere they are 3mm diameter axles, they are certainly thicker than the wheelset I got from Peter's Spares, from which I used the crank pins, and tyres for this chassis' rewheeling.

[Blink Bonny]

Ay up!

Might be worth pestering Alan Gibson - he does a lot of "drop in" conversion wheelsets with 3mm diameter axles. Provided you wheel up the chassis without any lubricant present, they hold their quartering well without any need for adhesives.

How do I know this? I got two 0-4-4Ts and a Midland Half-Cab wot say yeah!