Technical Question....How much of an interference fit should be allowed when pressing in a crown brass in the main driving box. How much on the toes and how much on the OD of the brass to box fit. This is for a CN engine with 10 1/2 inch journals and the centerline of the axle is 1 inch above the bottom of the toes. ThanksBruce Mowbray

The brass should be of the same diameter as the ID of the journal box. Then on the toes there should be +.030 on each toe for an ultimate press fit of 1.5 tons per inch of external brass diameter if the loco has cast iron boxes...if they are of cast steel then it should be +.045 on each toe for an ultimate press fit of 2.5 tons per inch of external brass diameter. It is important that the "bore" of the box be round and without any taper from one side to the other. If you find that the box is not true through the bore then contact Scott Lindsay of Steam operations, he can take care of such issues with no problem.