Co-Co bogies with P87 are tricky as the wheels can lock in curves which derails the leading or trailing axle. The solution to this is to allow extra lateral movement in the centre axle. We have to pack the back of the wheel to stop the Phosphor Bronze bearing from falling out of the pick up housing anyway so the solution is to pack the end axles with 20 thou Phosphor Bronze and the centre with 10 thou. Unfortunately each loco seems to be different as the centre axle isn’t always dead centre such as the 49 Class so some experimentation is required.
Clearly this pic shows the comparison in the wheels, and reminds me why I went down this path.
So here you can see the packing, what you may have noticed is that the gearing is not in the centre of the axle, this makes the packing interesting as the axle will slide a little further one way then the other but isn’t a major issue.
I have had a change of plan on the suspension, so this has made things a little slower then I thought it would be but there are some benefits to the new idea. I will do some testing this week and report back next week.
Bye for now..
Hi Andrew,
ReplyDeleteI've just got in contact with NWSL for some P87 wheels. I will watch your progress with interest.
Julian