Wald front racks are (95%) made to fit over 3/8" solid axles so it MUST fit over anything else. The handlebar clamps don't have to completely enclose the handlebars so handlebar size is usually a non-issue. Why not look at some images of properly installed racks for some insight into setting yours up. Admittedly, a track bike is not the type of bike Wald had in mind for that rack. But with some ingenuity almost anything can be made to work on a bicycle.

In the rare case that your rack is intended for eyelets and the bolt holes really are too small then you MUST use what are called 'P' clamps which will clamp around the fork legs and then bolt to the rack legs. I actually prefer that setup because the rack stays in place when the front wheel is removed. I haven't seen a track bike with actual Pista handlebars in some time but that is about the only handlebar that would have trouble with a Wald front rack. TL;DR: pictures would help, but I fear they would only help us. Ultimately your best bet may be to take this bike to a bike co-op OR the bike shop that sold you the rack. Bike co-op's are equipped to think outside the box for a reasonable charge (or no charge!) while any other bike shop other than the one that sold this will just shake their head and send you packing.