1

                                                                    EXHIBIT 99.4

                            U.S. TRUST COMPANY, N.A.

                             NOTICE TO PARTICIPANTS
                                     IN THE
                         WESTINGHOUSE AIR BRAKE COMPANY
                         EMPLOYEE STOCK OWNERSHIP PLAN

Dear ESOP Participant:

     Enclosed with this notice is a Joint Proxy Statement/Prospectus with
respect to the Special Meeting of Stockholders of Westinghouse Air Brake Company
(the "Company") to be held on August 23, 1999 (the "Special Meeting"). The
Special Meeting will be for the purpose of the approval and adoption of the
Agreement and Plan of Merger dated as of June 2, 1999, as amended, between the
Company and MotivePower Industries, Inc. and the merger. The Joint Proxy
Statement/Prospectus has been prepared by the Board of Directors of the Company
in connection with the business to be transacted at the Special Meeting. THE
ITEMS TO BE PRESENTED AT THE SPECIAL MEETING ARE IMPORTANT AND ARE DESCRIBED IN
THE PROXY MATERIALS BEING ENCLOSED WITH THIS NOTICE.

DIRECTIONS TO THE TRUSTEE

     Only U.S. Trust Company, N.A., as trustee (the "Trustee") of the
Westinghouse Air Brake Company Employee Stock Ownership Plan (the "ESOP"), can
vote the shares of the Company's stock (the "Shares") held by the ESOP. However,
under the terms of the Westinghouse Air Brake Company Employee Stock Ownership
Plan and Trust, you, as a participant in the ESOP, are entitled to instruct the
Trustee how to vote.

     Enclosed with this notice is a confidential voting instruction card which
is provided to you for the purpose of instructing the Trustee how to vote the
Shares concerning the above matters, which are described in the enclosed Joint
Proxy Statement/Prospectus. Your interest in these matters is important. Please
take the time to complete the voting instruction card and return it to the
Trustee. You may instruct the Trustee to vote for, against, or to abstain from
approval of such matters. If you do not provide instructions to the Trustee,
your Shares will be voted in accordance with the Westinghouse Air Brake Company
Employee Stock Ownership Plan and Trust.

     The Trustee will vote all shares of the ESOP in accordance with the
instructions set forth on the voting instruction cards which are received by the
Trustee on or before August 19, 1999, unless the Trustee determines such
instructions are contrary to the requirements of the Employee Retirement Income
Security Act of 1974, as amended ("ERISA").

CONFIDENTIALITY

     How you vote will not be revealed, directly or indirectly, to any officer,
any other employee or any director of the Company or to anyone else, except as
otherwise required by law. You should, therefore, instruct the Trustee to vote
the Shares in the manner you think best.
   2

VOTING DEADLINE

     Because of the time required to tabulate voting instructions from
participants before the Special Meeting, the Trustee must establish a cut-off
date for receiving your instruction card. The cut-off date established by the
Trustee is 5:00 P.M. Eastern Time on August 19, 1999. The Trustee cannot insure
that instruction cards received after the cut-off date will be tabulated.
Therefore, it is important that you act promptly and return your instruction
card on or before August 19, 1999, in the envelope provided for your
convenience. If the Trustee does not receive timely instructions from you with
respect to your Shares, the Trustee will vote such Shares in the manner directed
by the ESOP Committee, which is currently comprised of William E. Kassling,
Robert J. Brooks, and Kevin P. Conner.

     If you also hold shares of Common Stock of the Company directly and not
through the ESOP, you will receive, under separate cover, proxy solicitation
materials including a proxy card. That card should be used to vote the shares
you hold directly and CANNOT be used to direct the voting of shares held by the
ESOP.

FURTHER INFORMATION

     If you have questions regarding this information provided to you, you may
contact the Trustee at (800) 535-3093 between 11:30 A.M. and 7:00 P.M. Eastern
Time, Monday through Friday.

     Your ability to instruct the Trustee how to vote your Shares is an
important part of your rights as an ESOP participant. Please consider the
enclosed material carefully and then furnish your voting instructions promptly.

Dated July   , 1999

                                          U.S. Trust Company, N.A.,
                                          as Trustee of
                                          WESTINGHOUSE AIR BRAKE COMPANY
                                          EMPLOYEE STOCK OWNERSHIP PLAN