Yes, in fact you may find that none of it is taxable. Without having all your information I am referring you to a simple worksheet used to determine if any of you RRB is taxable. You can go to www.irs.gov search for 1040 instructions and download that publication. You do not need to print it, it would require a good deal of paper. The worksheet is on page 29 and is rather simple to complete.
Please feel free to ask me for additional assistance on this if you need help.