AMENDMENT DATED AS OF
                                  MAY 14, 1998

                                       TO

                             RIGHTS AGREEMENT DATED
                           AS OF MAY 15, 1997 BETWEEN
                L.B. FOSTER COMPANY (A DELAWARE CORPORATION) AND
                            AMERICAN STOCK TRANSFER &
                         TRUST COMPANY, AS RIGHTS AGENT



     Whereas,  as of May 15, 1997 L.B.  Foster Company,  a Delaware  corporation
("L.B.  Foster- DE"), and American  Stock  Transfer & Trust Company,  a New York
corporation   ("Rights  Agent"),   entered  into  a  Rights  Agreement  ("Rights
Agreement") setting forth the terms of certain Rights ("Rights") to be issued by
L.B.  Foster-DE to purchase  shares of Class A Common Stock,  par value $.01 per
share, of L.B. Foster-DE; and

     Whereas,  by action of the board of directors of L.B.  Foster-DE on May 15,
1997,  a  dividend  distribution  of one Right for each  share of Class A Common
Stock outstanding on May 21, 1997 was made, and the board further authorized the
issuance of one Right for each share of Class A Common Stock issued  between May
21, 1997 and the Distribution  Date (as defined in the Rights  Agreement),  each
Right, when exercisable, entitling the registered holder thereof to purchase one
share  of  Class A  Common  Stock  from  L.B.  Foster-DE  for  $30,  subject  to
adjustment; and

     Whereas,  at the close of  business on May 14,  1998,  L.B.  Foster-DE  was
merged ("Merger") into L.B. Foster Company,  a Pennsylvania  corporation  ("L.B.
Foster-PA"),  pursuant to a Plan of Merger whereby L.B.  Foster-PA  succeeded to
all the property,  rights and  obligations  of L.B.  Foster- DE, L.B.  Foster-DE
ceased to exist as a Delaware corporation, and each outstanding share of Class A
Common Stock of L.B.  Foster-DE  (including  shares held in the treasury) became
and was converted into one validly issued,  fully paid and non-assessable  share
of common stock, $.01 par value, of L.B. Foster-PA; and

     Whereas,  L.B.  Foster-PA  and the  Rights  Agent  wish to amend the Rights
Agreement to reflect and confirm that L.B. Foster-PA has succeeded to all of the
rights and obligations of L.B.  Foster-DE  thereunder and to reflect and confirm
certain conforming changes therein.

     Now,  therefore,  L.B.  Foster-PA  and the Rights  Agent,  intending  to be
legally bound, agree as follows:

     1. As of the time of the Merger, L.B. Foster-PA succeeded to all the rights
and obligations of L.B. Foster-DE under the Rights Agreement, and L.B. Foster-PA
replaced,  and hereby does replace,  L.B.  Foster-DE as the "Company"  under the
Rights Agreement.

     2. As of the time of the  Merger,  each  Right  theretofore  issued by L.B.
Foster-DE,  and  which  attached  to a share  of  Class A  Common  Stock of L.B.
Foster-DE,  became,  and hereby  does  become,  a Right,  when  exercisable,  to
purchase  from L.B.  Foster-PA  one share of common stock of L.B.  Foster-PA for
$30, subject to adjustment as provided in the Rights Agreement, such Right being
attached to the share of common stock of L.B. Foster-PA into which such share of
Class A Common Stock of L.B. Foster-DE has been converted.

     3. As of the time of the Merger,  all references in the Rights Agreement to
"Common  Stock"  became,  and hereby do become,  references to the common stock,
$.01 par  value  per  share,  of L.B.  Foster-PA,  and all  references  to other
securities of L.B. Foster-DE became,  and hereby do become,  references to other
securities of L.B. Foster-PA.

     4. One Right (as such number may be adjusted  pursuant to Section  11(p) of
the Rights Agreement) to purchase a share of common stock of L.B.  Foster-PA for
$30,  when  exercisable  and  subject to  adjustment  as  provided in the Rights
Agreement,  shall be issued for and attach to each share of common stock of L.B.
Foster-PA  issued after the time of the Merger,  whether an  originally-  issued
share or a share delivered from the treasury to which a Right had not previously
attached,  all in  accordance  with Section 3 of the Rights  Agreement as hereby
amended.

     5.  Section 32 of the Rights  Agreement is hereby  amended by  substituting
"Commonwealth of Pennsylvania" for "State of Delaware."

     6. Except as amended herein,  the Rights Agreement and all of its terms and
provisions shall remain in full force and effect.

     IN WITNESS  WHEREOF,  the parties  hereto have caused this  Amendment to be
duly executed as of the date first above written.


                                L.B. FOSTER COMPANY

                                By: /s/David L. Voltz
                                Name:    David L. Voltz
                                Title:   Vice President


                                AMERICAN STOCK TRANSFER &
                                TRUST COMPANY, as Rights Agent

                                By: /s/Herbert Lemmer
                                Name:    Herbert Lemmer
                                Title:   Vice President