UNITED STATES
                       SECURITIES AND EXCHANGE COMMISSION
                             Washington, D.C. 20549


                                  SCHEDULE 13G


                    Under the Securities Exchange Act of 1934
                                (Amendment No. 5)


                                 L.B. Foster Co.
       -----------------------------------------------------------------
                                (Name of Issuer)

                                  Common Shares
       -----------------------------------------------------------------
                         (Title of Class of Securities)

                                    350060109
        -----------------------------------------------------------------
                                 (CUSIP Number)


* The  remainder of this cover page shall be filled out for a reporting person's
initial filing on this form with respect to the subject class of securities, and
for any  subsequent  amendment  containing  information  which  would  alter the
disclosures provided in a prior cover page.

The information required in the remainder of this cover page shall not be deemed
to be "filed" for the purpose of Section 18 of the  Securities  Exchange  Act of
1934 ("Act") or otherwise  subject to the liabilities of that section of the Act
but  shall be  subject  to all other  provisions  of the Act  (however,  see the
Notes).

                               Page 1 of 4 Pages




                                  SCHEDULE 13G

CUSIP No. 350060109                                       Page 2 of 4 Pages

1     NAME OF REPORTING PERSON
      S.S. OR I.R.S. IDENTIFICATION NO. OF ABOVE PERSON

      Quaker Capital Management Corporation
      -------------------------------------

2     CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP*
                                                                          (a)
                                                                             ---

                                                                          (b) X
                                                                             ---
3     SEC USE ONLY    

4     CITIZENSHIP OR PLACE OF ORGANIZATION

            Pennsylvania
            ------------

   NUMBER OF                  5  SOLE VOTING POWER                       168,500
     SHARES
  BENEFICIALLY                6  SHARED VOTING POWER                     431,200
    OWNED BY
     EACH                     7  SOLE DISPOSITIVE POWER                  168,500
   REPORTING
    PERSON                    8  SHARED DISPOSITIVE POWER                431,200
     WITH

9     AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON
            599,700
            -------

10    CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (9) EXCLUDES
      CERTAIN SHARES
                     -------

      The Reporting  Person  disclaims  beneficial  ownership of 431,200  shares
      owned by its clients.


11    PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (9)

            5.96%
            -----

12    TYPE OF REPORTING PERSON*

           IA
          ----

                                Page 2 of 4 Pages




                         AMENDMENT NO. 5 TO SCHEDULE 13G
                               CUSIP NO. 350060109

      This  constitutes  Amendment  No. 5 to the Schedule 13G of Quaker  Capital
Management  Corporation  filed with the  Securities  and Exchange  Commission on
February 5, 1993 relating to the Common Stock of L.B.  Foster Co., as amended by
Amendment No. 1 filed with the Commission on February 10, 1994,  Amendment No. 2
filed with the  Commission on February 14, 1995,  Amendment No. 3 filed with the
Commission on February 15, 1996,  and Amendment No. 4 filed with the  Commission
on February 11, 1997 (the "Schedule 13G").

Item 4 of the  Schedule  13G is  hereby  amended  and  restated  to  read in its
entirety as follows:

Item 4.     Ownership
            ---------

            (a)   The Reporting Person, in its capacity as investment
                  adviser, may be deemed to be the beneficial owner of
                  431,200 shares of the Common Stock of the Issuer which are
                  owned by various investment advisory clients of the
                  Reporting Person in accounts over which the Reporting
                  Person has discretionary authority.  The filing of this
                  report shall not be construed as an admission that the
                  Reporting Person is, for purposes of Section 13(d) or 13(g)
                  of the Act, the beneficial owner of these securities.
                  Additionally, the Reporting Person and/or its principals
                  own 168,500 shares of the Common Stock of the Issuer.

            (b)   The  shares  covered  by this  report  represent  5.96% of
                  the Common Stock of the Issuer.

            (c)   None of the clients of the Reporting Person is known to own
                  more than 5% of the Common Stock of the Issuer.  The
                  Reporting Person shares voting and dispositive power over
                  the 431,200 shares owned by its clients and held in
                  accounts over which it has discretionary authority.  The
                  Reporting Person and/or its principals have sole voting and
                  dispositive power over the 168,500 shares owned by the
                  Reporting Person and/or its principals.

Item 6 of the  Schedule  13G is  hereby  amended  and  restated  to  read in its
entirety as follows:


                               Page 3 of 4 Pages




Item 6.     Ownership of More than Five Percent on
            Behalf of Another Person
            --------------------------------------

            431,200 of the shares with respect to which this report is filed are
            owned by a variety of investment  advisory  clients of the Reporting
            Person,  which clients are entitled to receive  dividends on and the
            proceeds  from the sale of such  shares.  No  client is known to own
            more than 5% of the class.


                                    SIGNATURE

After  reasonable  inquiry and to the best of my knowledge and belief, I certify
that the information set forth in this statement is true, complete and correct.


                                  QUAKER CAPITAL MANAGEMENT CORPORATION




February 12, 1998                 By:   /s/Mark G. Schoeppner
                                        -------------------------------
                                        Mark G. Schoeppner
                                        President


                                Page 4 of 4 Pages