Bachmann class 20's

[nigelcliffe]

I am about to go shopping for a new easy-to-get running loco, and a Bachmann class 20 is on the possibles list.

I plan to get the Ultrascale wheelset pack for it to convert to P4.

Are there any massive "gotchas" which I should worry about, or is this about as easy as "remove old wheelsets, put in new, possibly tweak pickups to touch wheels".

My aim is a reliable workhorse; take out of box and it will just run reliably with minimal hassle. It will probably be the full DCC-sound version, but the DCC side has no worries for me.


- Nigel

[davebooth]

Has any one converted a current Bachmann Class 20?
I'm not concerned about the where and wherefores of wheels et al but I'd like some advise as to how to get the axles out without damage to the bogie plastic mouldings.

[Dave Searle]

I plan to get the Ultrascale wheelset pack for it to convert to P4.

Are there any massive "gotchas" which I should worry about, or is this about as easy as "remove old wheelsets, put in new, possibly tweak pickups to touch wheels".

Yes it should be that easy, the tricky bit is working out how to unclip the cover off the underside of the bogie. Needs a small screwdriver to lever it off carefully.

Cheers,

Dave

Edit: I've just seen Keith Norgove's email in E4um pointing at his photos of the procedure: http://www.norgrove.me.uk/class20.html

[the fatadder]

The only other thing I can think of is that you may need to tweak out the sand pipes to line up with the new wheels, cant remember exactly where they are lined up with on the current model.

Wheels should be of the solid disk type, so tweaking the pickups will be as easy as they come,

the only other thing that comes to mind is taking care when removing the keeper plate, in some cases the plastic used on the keeper plate is very brittle and the end snap it (even so I haven't had one which has snapped which cant still be used.
The final thing to watch out for is the grease that Bachmann tend to jam a vast amount of between the gears and keeper plate, quite easy to make a bit of a mess.

[nigelcliffe]

Thanks Richard,
I now have the loco.
Out of the box, the sand pipes are aligned to sand the outside ends of the sleepers. Will be easy to tweak when the new wheels arrive.
I'll watch for the grease when dismantling, but first outing will be an hour or so running at a friend's OO. Much easier to deal with any warranty issues if they arise before I make changes !

regards,

- Nigel

[Brinkly]

Hi Dave,
viewtopic.php?f=21&t=243 I don't know, but it might be of some use.

Nick

[nigelcliffe]

That's my thread which started at about the same time.

Whilst I have a loco, I don't yet have the replacement wheels (not unreasonably; I only posted an order for them on Friday). The conversion looks simple, but until I actually have the wheels its hard to know if there are any "gotcha" moments.

The collection of "detailing" bits had me puzzled for a while, though I've decided that the packet is a generic packet for several locos - I can't see where the extra sand boxes fit, and whilst I thought some 20's had a ladder on the bonnet side (though a trawl of photos hasn't shown any, so my memory could be faulty!), there doesn't appear to be an obvious fixing point for it.

Final question (also posted to a DCC forum) - does anyone know if the neutral wire on the 21 pin decoder is powered by the ESU chip, and related, what the current limit might be on a circuit driven from that wire and the positive (blue) ? If I can't find an answer, there will be ways round the problem, but it may be amongst the simpler ways to get my DCC controlled couplers to work from the ESU chip.


- Nigel

[grovenor-2685]

I can't see where the extra sand boxes fit, and whilst I thought some 20's had a ladder on the bonnet side (though a trawl of photos hasn't shown any, so my memory could be faulty!), there doesn't appear to be an obvious fixing point for it.

The early class 20s had 4 sandboxes per bogie, ie on all 4 corners, fairly early in the production build this was reduced to two per bogie, on the outer ends. HAresnape has pics of D8040 and D8053 with 4 sandboxes so it definately went well beyong the pilot scheme. They also had ladders on the bonnet side which were removed as the 25kV electrification spread. You will see them on early pictures, and on the Hornby Dublo model.
The Ian Allen/R S Carter Diesel drawing book, 1975 version has a photo of D8000 as new with the ladder evident. Its on the RHS of the long hood immediately ahead of the fan, just to the left of the first bodyside door so the door will just open. I'm pretty sure they were only on the one side.
Regards

[nigelcliffe]

I can't see where the extra sand boxes fit, and whilst I thought some 20's had a ladder on the bonnet side (though a trawl of photos hasn't shown any, so my memory could be faulty!), there doesn't appear to be an obvious fixing point for it.

The early class 20s had 4 sandboxes per bogie, ie on all 4 corners, fairly early in the production build this was reduced to two per bogie, on the outer ends. HAresnape has pics of D8040 and D8053 with 4 sandboxes so it definately went well beyong the pilot scheme.

Thanks, that explains a few details I'd seen on photos. As mine is a headcode box version, its a later one (even if green), so will have two boxes per bogie (correct by Bachmann).

They also had ladders on the bonnet side which were removed as the 25kV electrification spread. You will see them on early pictures, and on the Hornby Dublo model.
The Ian Allen/R S Carter Diesel drawing book, 1975 version has a photo of D8000 as new with the ladder evident. Its on the RHS of the long hood immediately ahead of the fan, just to the left of the first bodyside door so the door will just open. I'm pretty sure they were only on the one side.

That makes sense with the model I have in my hands.
I guess mine (or Bachmann's design) is in the transition - there is a gap in the handrail where the ladder would rise on the RHS only.



The Ultrascale wheels have arrived, and were a doddle to fit; I had to remove a bit of the brake gear framing (ie. bits which hold the mouldings together, not the visible stuff), and there was a microscopic bit of flash on one wheel which caught on a lower brake bar (trivial to remove with scapel once identified). One axle had incorrect back=to=back, but 17.1mm was spotted before assembly, and easily adjusted.

Next step will be the decision on how many lights to fit, and how to link my electromagnetically controlled couplings back to the DCC chip. (And also what I do about running out of function buttons on my DCC throttle ; I already have some features mapped to buttons only available to me via a Sprog ).


- Nigel

[davebooth]

Sorry Nigel if I stole your thread, particularly as it all seems to have been transposed to where I started a similar enquiry.
I have been lurking, but not moving to far until 'delivery' of the replacement wheelsets. The ' ' around "delivery" is because I've been making them myself as I tend to do with most locos, although the last two converted diesels used Gibson products.
I've now delivered the wheels to myself and the conversion is complete - dead easy once you know how to get to the axles, but your input about the brake parts obstructing the wheels gave me confidence simply to hack away and not think!
The inputs about sand boxes and bonnet-side ladders has proved useful and as my model has now become D8128 and is assumed to be running circa 1966-70, it will have neither, making the conversion little more than changing the axles and adding a fair amount of grot.
There are however a couple more things I seek advice about:
I need a suitable 4 digit headcode for a goods train in the Manchester area. What did the individual digits stand for? Is there a publication available which allows one to build up a headcode?
I find the Bachmann windscreen wipers to be - should I be kind and say ... a little bulky! Are replacement wipers available from a trader such as Shawplan and if so, do I have to specify "Class 20"?

[David Knight]

Hi Dave,

There was some discussion about headcodes on E4um starting Jan 25 '09 that should be in the archives. There were some links given and some useful suggestions.

Shawplan does do wipers with plain and parallelogram varieties are both available. They are, as best I remember, generic rather than specific.

HTH

David

[grovenor-2685]

There was some discussion about headcodes on E4um starting Jan 25 '09 that should be in the archives. There were some links given and some useful suggestions.

Generally when posting on here it should not be assumed that the readers (who are many more than the one person you may be replying to) have access to private archives.
To help these are the links referred to:
http://www.zen39087.zen.co.uk/railway/ Covers years 1980 onwards
http://www.scot-rail.co.uk/page/Headcodes+Explained
One site that looked to have great potential but it is not in full working order yet:
http://www.headcode.co.uk/Index.htm the sticky factor being that it was launched in Jan 2006.

Regards

[davebooth]

There was some discussion about headcodes on E4um starting Jan 25 '09 that should be in the archives. There were some links given and some useful suggestions.

Generally when posting on here it should not be assumed that the readers (who are many more than the one person you may be replying to) have access to private archives.
To help these are the links referred to:
http://www.zen39087.zen.co.uk/railway/ Covers years 1980 onwards
http://www.scot-rail.co.uk/page/Headcodes+Explained
One site that looked to have great potential but it is not in full working order yet:
http://www.headcode.co.uk/Index.htm the sticky factor being that it was launched in Jan 2006.

Regards

Thank you Keith, the Scot-rail site helped with the headcodes.
Thanks too to Brian at Shawplan who guided me to the wipers I need (his type DP45-10), but also gave info about the headcodes.
I thought it only fair that this info. was past on.
First digit covers train type using 0 to 9 and "http://www.scot-rail.co.uk/page/Headcodes+Explained" list all ten, but this may help saving going there: 0 is light engine; 1 is xP; 2 is local P; 8 is slow goods.
Second digit uses A to Z and covers destination. However these seem to differ with differing operating areas
Third and fourth digits are again 0 to 9 and are sequentially related to departure time.
For my own layouts, area is Manchester and Brian gave me this:
'M' Midland inter-regional freight coming from outside the area
'T' Local trip workings from yards (Woodhead, Guide Bridge etc.)
'X' or 'Z' Special freight from outside the area.
'H' and 'J' were used for internal Manchester division workings.. (Chester,Wigan, Stoke, Preston etc...).
From this I shall probably use "8T35" which represents a slow goods on local trips starting about mid-morning (probably!?!~)

[IBlenkinsopp]

Yes, just did one last weekend, took me a while to figure out how to release the wheels. At the fore & aft end of each bogie, there are clips, which are partially hidden from view, but can be sprung with a couple of small screwdrivers or similar, there after an easy job to replace the wheels. I am ashamed to admit I had just about stripped the whole thing down before I realised this!!

Ian Bl.

[nigelcliffe]

Thanks for the information on wipers and headcodes - I will digest more thoroughly when my brain is back in gear.
I'm currently recovering slowly from my annual trip for up-hill skiing in Norway.

However, as a starter, how do you get the headcode panel out - is it lever from the front (damaging the trim?) or do you drill a small hole in the rear and push ?

- Nigel

[davebooth]

Thanks for the information on wipers and headcodes - I will digest more thoroughly when my brain is back in gear.
I'm currently recovering slowly from my annual trip for up-hill skiing in Norway.

However, as a starter, how do you get the headcode panel out - is it lever from the front (damaging the trim?) or do you drill a small hole in the rear and push ?

- Nigel

I used the point of a scalpel blade eased under what I thought was a plastic glazing cover. It isn't! - its a piece of about 0.060" thick black plastic with the number printed on and presumably gloss varnish representing the glass. It seems to be only a push-fit and perhaps your idea of drilling gently from the back will be less likely to cause damage, but my method was successful, although perhaps only down to good luck.
I hope to copy the idea and perhaps use blutak & a looser fit, so allowing for easy change of headcode to suit train.
I used 'Photoshop' with a 'layer' of black and a second layer with text in white. Ariel font at 14point seems a good match to the Bachmann code text. My idea is to cut 0.060" black platicard to minutely less than the Bachmann push-in bit, stick on my new, 'Photoshopped' headcode numbers, then gloss varnish. I'll report back when I've done it all.

[davebooth]

frontc20noheadcode.jpg

2headcodeW.jpg

I think my idea worked!
The new headcode panels are made from 0.060" plasticard, Photoshopped paper stuck on with MEK & then gloss varnished (actually clear nail polish Duckie!).
The original Bachmann ones are on top and the two different sizes - front larger - are fairly obvious.

[nigelcliffe]

I haven't tackled the panel or lights yet, but I have been tweaking....

On my 20, the bogies have an alarming amount of forwards/backwards shunt as the loco is reversed - the bogies move under the locomotive, and then the body of the locomotive moves to catch up with the moving bogies. I guess the slack in the bogie pivots allows for transitions from level to 1-in-6 gradients in a OO trainset.

My current "fix" is to insert 20 thou plasticard shims between the bogie tower and the main frames. This has dramatically reduced the visible shunt when the direction of running is changed; there is a tiny bit of movement but it requires very careful observation to spot it. Test running has been limited, but I can't see why the shims would wear particularly quickly.


The other area I've been tweaking is the behaviour of the DCC sound chip. By lowering the mid speed CV, and *increasing* the momentum settings, the loco and sound is more controllable on a small shunting layout. I also reduced the sound volume, and added a function key to control the volume (four different levels). I may get the sounds reprogrammed by Howes because the default Bachmann has rather too much high frequency, though that may wait until I've built some DCC controlled couplers for the loco; its currently running with static AJs.



- Nigel

[davebooth]

[quote="nigelcliffe"]I haven't tackled the panel or lights yet, but I have been tweaking....

On my 20, the bogies have an alarming amount of forwards/backwards shunt as the loco is reversed - the bogies move under the locomotive, and then the body of the locomotive moves to catch up with the moving bogies. I guess the slack in the bogie pivots allows for transitions from level to 1-in-6 gradients in a OO trainset.

My current "fix" is to insert 20 thou plasticard shims between the bogie tower and the main frames. This has dramatically reduced the visible shunt when the direction of running is changed; there is a tiny bit of movement but it requires very careful observation to spot it. Test running has been limited, but I can't see why the shims would wear particularly quickly.


Can I ask for more detailed information about your modification please Nigel. I'm not too sure about your "..between the bogie tower and the main frames".
Not only has my class 20 got that alarming amount of shunt, but even worse, when running in reverse the bogie tips fore and aft such that the inner axle of the rear bogie actually runs off the rail and derailment is far to frequent at any deviation from straight. It has taken some time for me to relate the two things as being the same fault; - take up the slop and stop both the shunt and the raised axle, but where and how do I get that 0.02"packing in?

[nigelcliffe]

I haven't tackled the panel or lights yet, but I have been tweaking....

On my 20, the bogies have an alarming amount of forwards/backwards shunt as the loco is reversed - the bogies move under the locomotive, and then the body of the locomotive moves to catch up with the moving bogies. I guess the slack in the bogie pivots allows for transitions from level to 1-in-6 gradients in a OO trainset.

My current "fix" is to insert 20 thou plasticard shims between the bogie tower and the main frames. This has dramatically reduced the visible shunt when the direction of running is changed; there is a tiny bit of movement but it requires very careful observation to spot it. Test running has been limited, but I can't see why the shims would wear particularly quickly.

Can I ask for more detailed information about your modification please Nigel. I'm not too sure about your "..between the bogie tower and the main frames".
Not only has my class 20 got that alarming amount of shunt, but even worse, when running in reverse the bogie tips fore and aft such that the inner axle of the rear bogie actually runs off the rail and derailment is far to frequent at any deviation from straight. It has taken some time for me to relate the two things as being the same fault; - take up the slop and stop both the shunt and the raised axle, but where and how do I get that 0.02"packing in?

The packing is a bit of 20thou, approx 10mm high and around 15mm wide (dimensions from memory). It is slightly curved when installed.

I pushed it in from the top of the chassis:
At the front remove the speaker and speaker mount, and the cab end remove the decoder and decoder sub-board. Then remove the worms (each fixed by a plate with screws to top). That gives access to the bogie towers, and the fore-aft shunt of the bogie should be easy to feel by hand. The plasticard is pushed down from the top to reduce the slop.

If the above is not enough, I can look at dismantling the loco to take a couple of pictures, but it will be at least four weeks before I will have time to do that.


regards,

- Nigel

[John Donnelly]

Apologies for resurrecting such an old thread but I've just, for my first P4 loco, converted the Bachmann 20 using Gibson wheels. Whilst the conversion has gone well well and the loco runs (although the pickups may need a bit more tweaking) I did find that, due to the increase in gauge, I'v had to remove the mouldings for the brake hangers and the brakes themselves.

Has anyone else who has done this conversion got a solution - I'm guessing I may be able to replace the plastic hangers and ties with brass strip to make it thin enough to fit back inside the bogies without fouling the wheels?

John

[Terry Bendall]

Has anyone else who has done this conversion got a solution

I have now done four Class 20s using the 14mm Black Beetle wheels from Branchlines. In all cases the brakes were left in place. All I needed to do was some scraping away of the inside of the plastic that the brake hangers are joined to, and a bit of scraping of the curve of the brake shoes themselves. If the brake shoes do have to be totally removed, one way of holding them back in place is to drill a 0.3 mm hole in the top of the brake hanger, glue in a piece of 0.3 wire and then drill a hole for the wire in the approapriate place in the bogie. There is not a lot of material to drill the hole in the top of the brake hanger but it can be done with care.

Terry Bendall

[John Donnelly]

Thanks Terry, much appreciated.

John

[Hardwicke]

I didn't alter the bogies at all regarding the brakes and have converted 1 with Ultrascale ( - took 5 minutes - fastest conversion I've ever done!!!) and 2 with Gibson wheels. They took about 20 minutes because I had to assemble them onto the axles. I note that I'll need some packing as mine move before the body does too.