Using a rolling road

[SMR248]

Over the years I seem to have acquired a lot of locos in various scales.

More recently I've tested these on a rolling road before putting them away and forgetting about them.

I've recently received a Duchess of Abercorn (with sound).  After some problems with HM 7000 (probably my fault) I got the engine running on the RR.  I was a bit surprised that there seemed to be quite a lot of "wobble" on the driving wheels.  I then ran it on some straight track and it seemed to run well but with a bit of fore and aft movement between the drivers.

The real test will be when I run it on my layout but HS2 seem to have got involved in that and the finish date for "stage 1" seems to have drifted somewhat (I won't mention the cost!).

I've resisted the urge to take it apart - I think it'll probably be fine (especially if I dont take it apart!).  That said there does appear to be quite a lot of "slop" in the mechanism.  My experience is that it's probably not unusual to have quite a lot of tolerance on the chassis / axle fit on something made for the British market but less so if it's intended for the German market (all scales, not just TT).

The RR is quite a useful tool but perhaps it has its limitations.

 

[ntpntpntp]

I find a lot of locos shimmy and wobble on a rolling road, even those which are perfectly smooth on the track.   I think it's the nature of the beast and the fact the wheels aren't all contacting the same piece of rail which helps with spreading the load and keeping wheels running smoothly.  
I have noticed a bit of slop / "take-up" in the mechanism of my WW.  I've not really run the Duchess enough yet to observe its behaviour.

I must admit I don't have an RR for 12mm gauge.  Who's RR are you using?   I have Bachruss "Saddles" for 9mm and 45mm gauge, and a Hornby one for 16.5mm

Edited 5 hours ago by ntpntpntp

[Silver Fox 17]

The bearings in the chassis have quite a bit of "slop". There is also a fair bit of play in the coupling rod to crank pin fit too.

[RB51]

2 minutes ago, ntpntpntp said:

Who's RR are you using?

This would be a good piece of information for we TT120 folk. R-

[SMR248]

I have a Mazero RR (made by Marion Zeller in Germany).  I've got four "dollies" for each of 9mm, 12mm and 16.5mm gauge.  It's well made and I'm happy with it although it's not compatible with some small N or 009 locos.

In the UK this system is (intermittently) available from DCC Automation (or directly from Frau Zeller).

Bizarrely there is another quite similar RR from another Zeller but I chose the Mazero one because, to me, it seemed to be a better quality product, albeit more expensive (of course!).

I did have the Bachrus saddles but I didn't particularly like this system because the saddles refused to stay on the tracks (a bit academic because they're no longer made).  The Mazero RR has its own frame so it does not sit on a piece of track so will allow a bit of "wiggle".

[SMR248]

1 hour ago, Silver Fox 17 said:

The bearings in the chassis have quite a bit of "slop". There is also a fair bit of play in the coupling rod to crank pin fit too.

Thanks, that's what I wanted confirmed.

It's strange because, in the distant past, whenever I read about making loco chassis, the books always described some sort of precision engineered item with reamed bushes and silver steel axles.  That's probably why I didn't go beyond reading about it.  Obviously there is a big difference between scratchbuilding and mass production.

[96RAF]

I use the Hornby RR with additional rollers installed. What you must remember is there is no resistance to running, thus you cannot load or stress the engine in any way.

[Rallymatt]

My first Duchess had an extreme amount of waddle on it and was replaced. One of the front bogie wheels was misfitted but the excessive shimmy on driving wheels was probably a out of alignment chassis, it’s sort of thing that does happen in the manufacturing process with this type of casting. Try it on track just be sure. A certain amount of waddle is normal, if all the joints were too tight, you would struggle in many ‘trainset’ curves. It’s amplified by the connecting rods being opposed on each side, not unlike the effect on a real steam engine.