EXHIBIT 3.55 CERTIFICATE OF FORMATION OF TSI FRANKLIN PARK, LLC UNDER SECTION 18-201 OF THE DEL. LIMITED LIABILITY COMPANY ACT This Certificate of Formation of TSI Franklin Park, LLC, dated as of August 3, 1998, is being duly executed and filed by Curt D. Buyum, as an authorized person, to form a limited liability company under the Delaware Limited Liability Company Act (6 Del. C. Section 18-101, et seq.) FIRST. The name of the limited liability company formed hereby is TSI FRANKLIN PARK, LLC. SECOND. The address of its registered office in the State of Delaware is Corporation Trust Center, 1209 Orange Street, in the City of Wilmington, County of New Castle. The name of its registered agent at such address is The Corporation Trust Company. IN WITNESS WHEREOF, the undersigned has executed this Certificate of Formation as of the date first above written. /s/ Curt D. Buyum ----------------------------------- Name: Curt D. Buyum Title: Authorized Person