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                                                                    Exhibit 10.6

                                THIRD AMENDMENT
                                      TO
                             INVESTMENT AGREEMENT


     This THIRD AMENDMENT TO INVESTMENT AGREEMENT (hereinafter referred to as
this "Agreement") dated as of January 15, 1999 is made and entered into by and
      ---------                                                                
among Framingham York Associates Limited Partnership, a Massachusetts limited
partnership ("FYA" or the "Purchaser"), Property Capital Trust, a Massachusetts
              ---                                                              
business trust (the "Trust"), and Maryland Property Capital Trust, Inc., a
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Maryland corporation (the "Company").
                           -------   

                                   RECITALS

     A.   The parties hereto entered into an Investment Agreement on June 18,
1998 (the "Original Agreement").
           ------------------   

     B.   The Original Agreement was amended by the parties hereto on August 7,
1998 (the "First Amendment").
           ---------------   

     C.   The Original Agreement and First Amendment were further amended on
October 16, 1998 (the "Second Amendment").
                       ----------------   

     D.   The parties hereto desire to amend the Original Agreement, the First
Amendment and the Second Amendment as provided herein.


     NOW, THEREFORE, in consideration of the mutual promises hereinafter set
forth and of other good and valuable consideration, the receipt and sufficiency
of which are hereby acknowledged, the parties hereto, intending to be legally
bound hereby, do hereby agree as follows:

1.   Section 9.1(c) is hereby amended by deleting the reference to "Monday,
February 1, 1999" and replacing it with "Monday, March 8, 1999."

2.   Section 9.1(d) is hereby amended by deleting the reference to "the 60th
day" and replacing it with "the 90th day."

3.   The parties hereby ratify and confirm that they continue to be bound by the
terms and provisions of the Original Agreement, the First Amendment and the
Second Amendment which, except as expressly modified hereby, shall continue in
full force and effect.

4.   This Agreement may be executed in counterparts, each of which shall be
deemed an original of all which, when taken together, shall be deemed one and
the same instrument.
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     IN WITNESS WHEREOF, the parties hereto have executed this Agreement as of
the date hereof.


                                    FRAMINGHAM YORK ASSOCIATES LIMITED
                                    PARTNERSHIP 


                                    By: /s/ Bruce A. Beal
                                       -----------------------------------------
                                       Bruce A. Beal, as General Partner
 

                                    By: /s/ Robert L. Beal
                                       -----------------------------------------
                                       Robert L. Beal, as General Partner

                                    PROPERTY CAPITAL TRUST


                                    By: /s/ Robert M. Melzer
                                       -----------------------------------------
                                       Robert M. Melzer, President and Chief
                                       Executive Officer


                                    MARYLAND PROPERTY CAPITAL TRUST, INC.


                                    By: /s/ Bruce A. Beal
                                       -----------------------------------------
                                       Name:  Bruce A. Beal
                                       Title: President

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