Noisy Bachmann Class 47

[JST]

My Bachmann class 47 is driving my round the bend! It runs well (DCC Lenz Silver decoder) but at slow speed it emits an intermittent grumbling/grinding sound. I assumed it was the dry motor bearing syndrome so took the thing apart completely, oiled the bearings and tested the motor directly with a dc supply. It ran perfectly. I assembled/lubricated the bogies and propshafts but the sound persists. The odd thing is that if I run it at shunt speed towards a buffer it makes the noise until it hits the buffers and then sits there with all wheels slowly spinning on the rails in perfect silence! The only thing I can think of is there may be some sort of issue with the gears in the bogies which goes away when the wheels are under a bit of tension when held against the buffers with the wheels spinning on the track.

 

Any ideas anyone?

[34theletterbetweenB&D]

Does the silencing effect when stationary apply equally whichever end is on the buffers? This description:

On ‎07‎/‎07‎/‎2020 at 12:31, JST said:

...at slow speed it emits an intermittent grumbling/grinding sound...

...I have experienced once on a class 24 mechanism. It was one of the drive couplers in the flywheels that was slipping slightly andf intermittently at slow speed, and 'grumbling' is how I characterised it. Disappeared at speed, and was rare with the slipping end leading.

[atom3624]

Are the bogie sideframes mounted correctly?

 

I have a blue BR 47 which had a slightly deformed bogie base / sideframe.

I could use the 'good one' on both bogies and it was perfect, but the other one caused 'issues', mainly related to slight deformation, and particularly the alignment of the brake shoes.

 

Realigning / reshaping nearly cured it, but still had issues, so I got a replacement from Bachmann - 'fair' price.

The replacement cured everything - running like it should do, no issues, greate locomotive.

 

Might be a consideration?

 

Al.

[Matt]

The other issue it might be is if the three wheelsets in the bogie are not all sitting at same level - early class 37s were infamous of this - with centre axle slightly lower than outer axles, causing the outer wheels to "chatter" on the rail as the weight is taken through the centre wheelset and outer wheels intermittently leave/impact track.  I can't recall if I've had a 47 do this but many of my 37s do and it can sound like drive noise.  There is an easy mod I believe though i''ve never got around to doing mine (involves removing centre axle and deepening slot in which sits slightly).

 

M

[JST]

Thanks for all this. As soon as I can get back to the railway room I will check these ideas out and report back.

 

Many thanks for your help.

[tractor_37260]

Easy way to check if it's drive train noise remove the bogie frames then pull out both centre wheels/axles and then try it, if it now runs quieter then one or both of the centre axles are lower than the outer ones causing the noise. 

 

HTH

 

 

 

 

 

 

 

 

[JST]

Well I went to try some of the ideas given here only to find the loco had cured itself! I can only think that the gear train in the bogie(s) had dried out and the lubrication I gave it has now seeped into the gear run. Anyway, I will monitor the situation.

Again, thanks for your help.