Welcome Guest ( Log In | Register )

 
Reply to this topicStart new topic
> Bachmann's Peppercorn A2, Failed on the road!
34C
post 23 Oct 2020, 14:07
Post #1


In depth idiot
**********

Group: Members
Posts: 7,297
Joined: 31-May 07
Member No.: 1,818



Had a little 'operational hiccup' yesterday evening of the sort I rather like, an A2 stalled tripping out the DCC system. (I knew this loco was the cause because I saw the spark as I was watching it start away.) What happens on such occasions is that the loco concerned is ruled to have 'failed' so comes off, and the nearest suitable alternative loco is brought on to work the train forward. Makes for some extra loco moves which is operationally interesting, and handily there was a V2 light engine movement just in rear going to pick up a set of empty racing pigeon vans; so suitable traction to hand for a prompt recovery, the pigeon empties can wait.

But what of the A2 now on the naughty step? I was pretty sure of what I would find, sure enough the leading bogie wheel flanges have worn through the paint on the cast footplate underside, and there's the source of the short that tripped the system. (Had this happen previously with leading pony truck and bogie wheelsets on several Bachmann models with their frequent use of cast metal footplates. The fix is very easy, just cut slightly deeper arches where the witness marks indicate contact regularly occurs, and smear with a little Araldite as 'belt and braces'.)

But there's a puzzle in this. I have both A1s and A2s on the layout, both by Bachmann, and structurally everything in common, apart from the variations corresponding to the two prototype's (minor) dimensional differences. The A1s get far more running and have been in use twice as long as the A2s. The A1s required much adjustment to pull well, (this was well documented back in the day on various forums) but the A2s which became available ten years later were pretty much trouble free. Only added a little weight to mine - carefully maintaining the C of G in the centre of the coupled wheelbase - to ensure the restart capability on a gradient, but they are still lighter than the A1s.

But it is only the A2s which have developed this shorting, and a glance at the A1s shows no evidence of bogie wheel flange contact on the footplate underside, whereas this has now occurred on all my A2s. Yet the A1 is the longer vehicle, and with the same clearance between the flanges and the footplate castings - as best I can assess it with feeler gauges - should be the more prone to this event on grounds of simple geometry when moving onto the transition at the foot of a rising gradient. So something else is going on, but I don't know what...
Go to the top of the page
 
+
Julian2011
post 23 Oct 2020, 20:33
Post #2


C55
*******


Group: Members
Posts: 2,375
Joined: 29-January 11
From: South Wiltshire - OO and an intended toy in N
Member No.: 9,766



Different wheel flange diameters? Possibly thinner later model flanges, but larger diameter, to compensate?

Julian


--------------------
Go to the top of the page
 
+
34C
post 24 Oct 2020, 08:51
Post #3


In depth idiot
**********

Group: Members
Posts: 7,297
Joined: 31-May 07
Member No.: 1,818



QUOTE (Julian2011 @ 23 Oct 2020, 21:33) *
Different wheel flange diameters? ...

Thanks, that's part of what I was poking at with the feeler gauges in the gap between the flange tops and the footplate underside.

Now, when I first had the A2 I made a pretty thorough survey of the commonalities with the A1, and the bogies complete are - within manufacturing variance - identical (sensibly enough, they were on the real thing). But that survey was mostly in respect of sparing, which parts can I swap about at need? (This is a strategy to cope with spares supplies being unreliable. Bachmann seemingly have no knowledge of mechanism parts commonality between models in their range.)

Clearly I need to be unlazy, and run the mic. over the wheelsets, among other things, when I feel like digging into this. But it's far more fun to run the trains, than operate the loco repair shop: that tends to wait until I have ideas of what to look for.
Go to the top of the page
 
+
Julian2011
post 24 Oct 2020, 09:47
Post #4


C55
*******


Group: Members
Posts: 2,375
Joined: 29-January 11
From: South Wiltshire - OO and an intended toy in N
Member No.: 9,766



Just another thought, I should have been awake enough to mention before, is there any spring on them and if so could they be at a different tensions?

Julian


--------------------
Go to the top of the page
 
+
34C
post 24 Oct 2020, 12:52
Post #5


In depth idiot
**********

Group: Members
Posts: 7,297
Joined: 31-May 07
Member No.: 1,818



The springing, yes, I think this may be where investigation will have to focus. The bogie has a spring, as does the leading coupled wheel, and also the rear truck slide; and this same arrangement is found on Bachmann's A1 and A2 models.

I never looked at the springing of the leading coupled wheelset on the A2, because the A2s 'performed' as required straight out of the box. Among other mods to the A1s, all the springing was significantly altered, cut down to be softer on the carrying wheels, and a higher force substitute spring on the leading driver, because the factory item was simply too soft.

That's a good place to start, apply more spring force to the stopped A2's leading driver, and run it over the trouble spot to see if that prevents a short.

Go to the top of the page
 
+
34C
post 26 Oct 2020, 09:29
Post #6


In depth idiot
**********

Group: Members
Posts: 7,297
Joined: 31-May 07
Member No.: 1,818



Fault was obvious enough once I had the keeper plate off, the coil spring on the leading driver had broken so was having little effect. Should have looked at my notes* earlier, I had changed the leading driver spring on this A2 after first testing it because the original was ineffective due to a very deep location. Having searched the spares stash for a suitable replacement, the other two A2s will get their's replaced too when they come up for their internal lubrication check.

*Note to self, consult the notes you made, and write the notes you make a bit more clearly in future...
Go to the top of the page
 
+
Julian2011
post 26 Oct 2020, 11:19
Post #7


C55
*******


Group: Members
Posts: 2,375
Joined: 29-January 11
From: South Wiltshire - OO and an intended toy in N
Member No.: 9,766



Glad to see it turned out well and with a simple solution.

Julian


--------------------
Go to the top of the page
 
+
34C
post 26 Oct 2020, 15:35
Post #8


In depth idiot
**********

Group: Members
Posts: 7,297
Joined: 31-May 07
Member No.: 1,818



Thanks. I have made the effort to write 'read your notes' on the maintenance schedule board. I will probably need a reminder somewhere else to read and take action on what's on the board too...
Go to the top of the page
 
+
dwb
post 26 Oct 2020, 17:54
Post #9


Station cat
Group Icon



Group: Moderators
Posts: 9,591
Joined: 17-January 06
From: Central southern England
Member No.: 507



QUOTE
Note to self, consult the notes you made, and write the notes you make a bit more clearly in future...

A rather familiar refrain for me too .... wink.gif

Glad to hear it's sorted now.

David


--------------------
Want to post pictures in your posts but don't know how? Instructions can be found in this topic
Almost all the photos I post can be found in my albums. There are 900+ at present. Click the Gallery button to the left of this post.
Go to the top of the page
 
+
kristopher1805
post 26 Oct 2020, 20:28
Post #10


Minister of Transport
Group Icon



Group: Plus+
Posts: 5,795
Joined: 23-July 10
From: UK Devon
Member No.: 8,315



Tell me please I have both A1 and A2's and use the A2 quite a lot although P2 is having a go at the moment, however did the decoder blow up? if so I'll take it more seriously as at £20 plus I do not like to collect more blown decoders!
Go to the top of the page
 
+
34C
post 26 Oct 2020, 23:04
Post #11


In depth idiot
**********

Group: Members
Posts: 7,297
Joined: 31-May 07
Member No.: 1,818



QUOTE (kristopher1805 @ 26 Oct 2020, 21:28) *
Tell me please I have both A1 and A2's and use the A2 quite a lot although P2 is having a go at the moment, however did the decoder blow up?...

No damage to the decoders, in this case or any of the previous such stoppages from short circuits across the rails via the loco structure. After a DCC system reset, all the locos immediately restarted normally, including this recent event with the A2.
Go to the top of the page
 
+

Reply to this topicStart new topic
1 User(s) are reading this topic (1 Guests and 0 Anonymous Users)
0 Members:

 



RSS    Lo-Fi Version Time is now: 4th December 2020 - 23:54