UNION PACIFIC CORPORATION

Exhibit 10(a)

UNION PACIFIC CORPORATION

STOCK UNIT GRANT AND DEFERRED COMPENSATION PLAN

FOR THE

BOARD OF DIRECTORS

(Effective December 1, 1978—as Amended April 30, 1987,

January 1, 1995, January 25, 1996, February 26, 1998,

January 28, 1999, May 27, 1999, May 31, 2001 and January 1, 2003)

Union Pacific Corporation

Stock Unit Grant and Deferred Compensation Plan

for the Board of Directors

As Amended as of January 1, 2003

The purpose of this Plan is to permit grants of Stock Units to Directors to align their interests with those of stockholders, and to provide a means for deferring payment of all or a portion of any cash compensation, excluding expenses, payable to Directors for their service on the Board of Directors (the “Board”) of Union Pacific Corporation (the “Company”) in accordance with Article II, Section 4 of the By-Laws of Union Pacific Corporation. Such compensation eligible to be deferred, not including any grants under paragraph 3, is referred to herein as “Compensation”.

Any individual (a “Director”) serving as a member of the Board as of the effective date of this Plan or who subsequently becomes a member is eligible under this Plan, other than members who are employees of the Company or any of its subsidiaries.

An election to defer Compensation is to be made on or before December 31 of any year for Compensation for services as a member of the Board for the following and later calendar years. In addition to deferrals of 1995 Compensation elected in the previous year, at any time prior to March 31, 1995, a Director may elect to defer additional Compensation to be paid for services in the last three quarters of 1995.

An election to defer is a continuing election until changed by the Director on or before December 31 of any year for the then following and later calendar years. However, once an election is made (and effective), subsequent elections will have no effect on the amounts, timing and manner of payment covered by the previous election, except as provided under “Manner of Payment”.

Any newly elected Director who was not a Director on the preceding December 31 may elect, before his term begins, to defer Compensation for services as a member of the Board for the balance of the calendar year following such election.

Forms shall be made available to Directors each year for the purpose of making or changing their election.

All or any portion, in multiples of 1%, of a Director’s Compensation may be deferred.

Each Director shall have a Stock Unit Account and may have one or more Other Accounts (together, the “Accounts”). Amounts deferred pursuant to paragraph 4 may be credited to any Account, at the election of the Director made at the time of the deferral election, in multiples of 1% of such Director’s Compensation. A Director may change the Account to which any quarterly installment of such

Director’s Compensation so deferred is to be credited at any time on or before the fifth business day prior to the date such quarterly installment is to be credited. Amounts deferred and credited to the Stock Unit Account shall be converted into whole Stock Units on the basis of the Fair Market Value of the Company’s Common Stock on the first business day of the month following the quarter in which the Compensation was earned, and cash shall be credited to the Stock Unit Account in lieu of any fractional Stock Unit. In addition, (i) on or prior to March 31, 1995, each Director shall have a one-time election to transfer all or any part of the balance of his or her Other Account to the Stock Unit Account based on the Fair Market Value of the Company’s Common Stock on April 3, 1995, (ii) at any time, a Director may transfer all or any part of the balance of any of his or her Other Accounts to another of his or her Other Accounts subject to any regulations regarding such transfer adopted by the Board and (iii) at any time on or after the 30th day after the date of a Director’s termination from the Board, such Director may transfer all or any part of the balance of any of his or her Accounts to another of his or her Accounts, pursuant to any regulations regarding such transfers adopted by the Board.

On the payment date for each cash dividend or other cash distribution with respect to the Company’s Common Stock, each Director’s Stock Unit Account shall be credited with an amount equal to the amount of the per share dividend or distribution, multiplied by the number of Stock Units in such Account, and, if such Director is then serving as a member of the Board, shall be converted into whole Stock Units on the basis of the Fair Market Value of the Company’s Common Stock on the payment date for such dividend or distribution, and cash shall be credited to the Stock Unit Account in lieu of any fractional Stock Units. If a Director is no longer serving as a member of the Board on the payment date for such dividend or distribution, the amount representing such dividend or distribution shall be paid out of the Stock Unit Account to such Director as soon as practicable after the payment date for such dividend or distribution.

Except as provided in the preceding sentence, any cash credited to a Director’s Stock Unit Account shall be added to other cash credited to such Account and converted into a whole Stock Unit on the date sufficient cash exists to purchase a whole Stock Unit, based on the Fair Market Value of the Company’s Common Stock on such date. In the event of a subdivision or combination of shares of Company Stock, the number of Stock Units credited to the Stock Unit Accounts on the effective date of such subdivision or combination shall be proportionately subdivided or combined as the case may be. No adjustment shall be made in Stock Units in connection with the issuance by the Company of any rights or options to acquire additional shares of Company Common Stock or securities convertible into Company Common Stock. In the event of any stock dividend or reclassification of Company Common Stock, any merger or consolidation to which the Company is a party, or any spinoff of shares or distribution of property other than cash with respect to the Company Common Stock, the Committee shall cause appropriate adjustments, if any, to be made in the Stock Units to reflect

such stock dividend, reclassification, merger or consolidation, spinoff or distribution of property.

Other Accounts shall have such name, and be charged or credited pursuant to such method, as the Board shall determine upon establishment of such Other Account, and the Board may change such name or method for any such Other Account, but no such change shall reduce any amount previously accrued in a Director’s Other Account.

All distributions from Accounts shall be made in cash. For purposes of distributions from the Stock Unit Account, each Stock Unit shall be converted into an amount of cash equal to the Fair Market Value of one share of the Company’s Common Stock on the first business day of the month in which such distribution is made. The Director must elect the timing and manner of payment: (a) in the case of deferred Compensation, at the same time and on the same form he elects a deferral of Compensation, (b) in the case of a Stock Unit grant under 3.a., on or prior to the time an election to defer the accompanying Compensation would have been required to be made, (c) in the case of a Stock Unit grant under 3.b., at the same time as the Election referred to therein, and (d) in the case of a Stock Unit grant under 3.c., prior to the time the Director receives such grant

The lump sum or first installment is to be paid in January of the year following the year of termination or retirement or in January of the year selected by the Director, as applicable, and any remaining installments in January of each succeeding year until the total balance is paid. Distributions from the Stock Unit Account in installments shall be based on equal numbers of Stock Units in each installment.

In the event of the death of a Director then serving as a member of the Board or a terminated or retired Director entitled to a distribution under this Plan, the balance of the Accounts shall be payable to the estate or designated beneficiary in full during the January of the year following the year of such Director’s, terminated Director’s or retired Director’s death.

The Director may designate his beneficiary at the same time he elects deferral of Compensation. However, the latest designated beneficiary will be the beneficiary or beneficiaries for the total of all distributions from the Accounts. The designated beneficiary may be changed at any time on a form provided by the Corporate Secretary, provided that no designation will be effective unless it is filed with the Corporate Secretary prior to the Director’s death.

A Director may request a withdrawal from an Other Account (not to include the Director’s Stock Unit Account) prior to the date specified in the Director’s deferral election by filing a request in writing with the Corporate Secretary. Payment will be made to the Director within thirty (30) days of such request. Any withdrawal under this Section will be charged with a 10% early withdrawal penalty that will be withheld from the amount withdrawn and such amount withheld shall be irrevocably forfeited.

The liability of the Union Pacific Corporation to any Director, terminated Director, retired Director or his estate or designated beneficiary under the Plan shall be that of a debtor only pursuant to such contractual obligations as are created by the Plan, and no such obligation of Union Pacific Corporation shall be deemed to be secured by any assets, pledges, or other encumbrances on any property of Union Pacific Corporation.

Except to the extent of the rights of a designated beneficiary, no distribution pursuant to, or interest in, the Plan may be transferred, assigned, pledged or otherwise alienated and no such distribution or interest shall be subject to legal process or attachment for the payment of any claims against any individual entitled to receive the same.

All questions pertaining to the construction, regulation, validity and effect of the Plan shall be determined in accordance with the laws of the State of Utah.

The Board of Directors of the Union Pacific Corporation at its sole discretion may amend, suspend or terminate the Plan at any time. However, any such amendment, suspension or termination of the Plan may not adversely affect any Director’s or his beneficiary’s rights with respect to Compensation previously deferred.

Administration of the Plan will be coordinated by the Corporate Finance Department. Administration will include, but not be limited to, crediting of deferred compensation, dividends and accrued interest to individual Director accounts and ultimate disbursement of deferred amounts.

This Plan shall become effective December 1, 1978, applicable only to compensation for services after December 31, 1978, provided that the provisions hereof related to Stock Units shall be effective January 1, 1995.