Derailment

[Rsjs]

My flying Scotsman is derailing over every point. The front bogie seems not to follow the points.

[What About The Bee]

Hello @Rsjs

Welcome Aboard!

To help narrow down the cause, would you happen to have the Hornby number?  It would start with an 'R', like R1234.  Very likely on the underside of the Flying Scotsman and also definitely on the box it came it.

Bee

[Rsjs]

It’s R3284TTS

[What About The Bee]

Thank you for that.

How a locomotive moves through a set of points is a system of design.  That system requires all of the design values be within a small window of tolerance.

Do other locomotives go through your points?  If they do, and this one does not, we can focus on the locomotive.  Otherwise, we must consider other parts of the design.

I assume you checked the back to back of the wheels on the front bogie?  They should be ~14.3mm or there abouts.  This is a very common cause of derailment.

If the back to back is okay, then slowly push the locomotive through an offending point.  Watch closely to see where the wheels and point have a problem and report back.  Is a wheel catching on the check rail?  Bouncing on the frog?  Or perhaps the bogie is catching on the locomotive underside.

Bee

[ColinB]

2 hours ago, Rsjs said:

My flying Scotsman is derailing over every point. The front bogie seems not to follow the points.

It is probably the front bogie, I have had many A1s that do that. It could be back to back spacing on the bogie wheels, the bogie bolt that holds the bogie to the bogie bracket is not long enough or you either need to add a light spring between the bogie and the bogie bracket. On some of mine I have had to add a spring on others I have had to remove it. Initially try measuring the distance between the wheels on the front bogie (back to back spacing) that is the favorite.

[atom3624]

The spring used to be there as well I'm fairly certain.  Totally agree with CB's comments.

I normally check the B2B, then I'll slightly bend the T-mount bracket to bring a tiny bit more weight / less possibility for the wheels to leave, but without them lifting the drivers off the track - take care here or you'll lose traction.

How are the wheels of the pony truck - do they clear the tracks when the body swings on curves?  Some catch the tracks and can take the locomotive off this way.

Al.

[RDS]

@Rsjs you certainly should not have to make any modifications to your Loco (assuming you bought it new and no-one has messed with it before).

Your points need to be perfectly flat and I have added an extra fixing pin to the centre of most of my points because even the slightest 'out of flat' can cause problems.  To do this you need to drill a hole in the sleeper right in the centre of the point, with a 1mm drill.  You can easily check if this is going to make a difference by pressing down in the centre of your points and ensuring there is NO movement.  The back to back measurement as mentioned above is also important.