Is royalty a part of operating surplus?

Yes,

Royalty is part of the operating surplus.

Explanation:-

Operating surplus refers to income from Property and entrepreneurship. It includes the following items

Operating surplus = Income from Property + Income from entrepreneurship

Income from Property consists of

1. Income from Rent
2. Income from Royalty
3. Income from Interest

Income from entrepreneurship consists of

1. Income from Profit.

Thus the components of Operating surplus can be rewritten as:

Operating Surplus = Rent + Royalty + Interest + Profit