Canadian Pacific Railway Ltd (CP): Bill Ackman Unloads 4.10 Mln Shares

SECURITIES AND EXCHANGE COMMISSION

Washington, D.C. 20549

SCHEDULE 13D

(Rule 13d-101)

INFORMATION TO BE INCLUDED IN STATEMENTS FILED PURSUANT

TO § 240.13d-1(a) AND AMENDMENTS THERETO FILED

PURSUANT TO § 240.13d-2(a)

Under the Securities Exchange Act of 1934

(Amendment No. 15)*

Canadian
Pacific Railway Limited

(Name of Issuer)

Common Shares

(Title of
Class of Securities)

13645T100

(CUSIP Number)

Stephen
Fraidin, Esq.

Steve Milankov, Esq.

Pershing Square Capital Management, L.P.

888 Seventh Avenue, 42nd Floor

New York, New York 10019

(212) 813-3700

with
a copy to:

Alan J. Sinsheimer, Esq.

Sullivan & Cromwell LLP

125 Broad Street

New
York, New York 10004

(212) 558-4000

(Name, Address and Telephone Number of Person Authorized to Receive Notices and Communications)

April 22, 2016

(Date of Event Which Requires Filing of This Statement)

If the filing person has
previously filed a statement on Schedule 13G to report the acquisition that is the subject of this Schedule 13D, and is filing this schedule because of §§ 240.13d-1(e), 240.13d-1(f) or 240.13d-1(g), check the following box. ¨

Note: Schedules filed in paper format shall include a signed original and five copies of the schedule, including all exhibits. See
§ 240.13d-7 for other parties to whom copies are to be sent.

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

The information required on 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).

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CUSIP No. 13645T100		Page 2 of 7 Pages

1		NAME OF REPORTING PERSON Pershing Square Capital Management, L.P.
2		CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP (SEE INSTRUCTIONS) (a)  ¨        (b)  ¨
3		SEC USE ONLY
4		SOURCE OF FUNDS (SEE INSTRUCTIONS) OO (See Item 3)
5		CHECK IF DISCLOSURE OF LEGAL PROCEEDINGS IS REQUIRED PURSUANT TO ITEMS 2(d) OR 2(e) ¨
6		CITIZENSHIP OR PLACE OF ORGANIZATION Delaware
NUMBER OF SHARES BENEFICIALLY OWNED BY EACH REPORTING PERSON WITH				7		SOLE VOTING POWER 0
				8		SHARED VOTING POWER 9,840,890
				9		SOLE DISPOSITIVE POWER 0
				10		SHARED DISPOSITIVE POWER 9,840,890
11		AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON 9,840,890
12		CHECK IF THE AGGREGATE AMOUNT IN ROW (11) EXCLUDES CERTAIN SHARES (SEE INSTRUCTIONS) ¨
13		PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (11) 6.4% (1)
14		TYPE OF REPORTING PERSON (SEE INSTRUCTIONS) IA

(1)	This calculation is based on 153,059,426 common shares, no par value (Common Shares), of Canadian Pacific Railway Limited (the Issuer) outstanding as of April 18, 2016 as reported in the Quarterly Report on Form 10-Q, filed by the Issuer on April 20, 2016 (the 10-Q).

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CUSIP No. 13645T100		Page 3 of 7 Pages

1		NAME OF REPORTING PERSON PS Management GP, LLC
2		CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP (SEE INSTRUCTIONS) (a)  ¨        (b)  ¨
3		SEC USE ONLY
4		SOURCE OF FUNDS (SEE INSTRUCTIONS) OO (See Item 3)
5		CHECK IF DISCLOSURE OF LEGAL PROCEEDINGS IS REQUIRED PURSUANT TO ITEMS 2(d) OR 2(e) ¨
6		CITIZENSHIP OR PLACE OF ORGANIZATION Delaware
NUMBER OF SHARES BENEFICIALLY OWNED BY EACH REPORTING PERSON WITH				7		SOLE VOTING POWER 0
				8		SHARED VOTING POWER 9,840,890
				9		SOLE DISPOSITIVE POWER 0
				10		SHARED DISPOSITIVE POWER 9,840,890
11		AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON 9,840,890
12		CHECK IF THE AGGREGATE AMOUNT IN ROW (11) EXCLUDES CERTAIN SHARES (SEE INSTRUCTIONS) ¨
13		PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (11) 6.4% (2)
14		TYPE OF REPORTING PERSON (SEE INSTRUCTIONS) OO

(2)	This calculation is based on 153,059,426 Common Shares outstanding as reported in the 10-Q.

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CUSIP No. 13645T100		Page 4 of 7 Pages

1		NAME OF REPORTING PERSON William A. Ackman
2		CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP (SEE INSTRUCTIONS) (a)  ¨        (b)  ¨
3		SEC USE ONLY
4		SOURCE OF FUNDS (SEE INSTRUCTIONS) OO (See Item 3)
5		CHECK IF DISCLOSURE OF LEGAL PROCEEDINGS IS REQUIRED PURSUANT TO ITEMS 2(d) OR 2(e) ¨
6		CITIZENSHIP OR PLACE OF ORGANIZATION U.S.A.
NUMBER OF SHARES BENEFICIALLY OWNED BY EACH REPORTING PERSON WITH				7		SOLE VOTING POWER 0
				8		SHARED VOTING POWER 9,840,890
				9		SOLE DISPOSITIVE POWER 0
				10		SHARED DISPOSITIVE POWER 9,840,890
11		AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON 9,840,890
12		CHECK IF THE AGGREGATE AMOUNT IN ROW (11) EXCLUDES CERTAIN SHARES (SEE INSTRUCTIONS) ¨
13		PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (11) 6.4% (3)
14		TYPE OF REPORTING PERSON (SEE INSTRUCTIONS) IN

(3)	This calculation is based on 153,059,426 Common Shares outstanding as reported in the 10-Q

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This Amendment No. 15 relates to the Schedule 13D filed on October 28, 2011, as amended prior to the
date of this Amendment (as so amended, the Original 13D), by (i) Pershing Square Capital Management, L.P., a Delaware limited partnership (Pershing Square), (ii) PS Management GP, LLC, a Delaware
limited liability company (PS Management) and (iii) William A. Ackman, a citizen of the United States of America (together with Pershing Square and PS Management, the Reporting Persons), relating to common
shares, without par value (the Common Shares), of Canadian Pacific Railway Limited, a corporation organized under the Canada Business Corporations Act (the Issuer). Capitalized terms used but not defined herein
shall have the meaning set forth in the Original 13D.

Item 1. Security and Issuer.

Item 1 of the Original 13D is amended and supplemented as follows:

The Reporting Persons beneficially own an aggregate of 9,840,890 Common Shares (the Subject Shares).

Item 5. Interest in the Securities of the Issuer.

Items 5(a) and (b) of the Original 13D are amended and restated as follows:

(a), (b)

Based upon the Quarterly Report on Form 10-Q, filed by
the Issuer on April 20, 2016, there were 153,059,426 Common Shares outstanding as of April 18, 2016.

Based on the foregoing, the Subject Shares
beneficially owned by the Reporting Persons represent approximately 6.4% of the Common Shares outstanding.

Pershing Square, as the investment adviser to
the Pershing Square Funds, may be deemed to have the shared power to vote or direct the vote of (and the shared power to dispose or direct the disposition of) the Subject Shares. As the general partner of Pershing Square, PS Management may be deemed
to have the shared power to vote or to direct the vote of (and the shared power to dispose or direct the disposition of) the Subject Shares. By virtue of William A. Ackmans position as the Chief Executive Officer of Pershing Square and
managing member of PS Management, William A. Ackman may be deemed to have the shared power to vote or direct the vote of (and the shared power to dispose or direct the disposition of) the Subject Shares and, therefore, William A. Ackman may be
deemed to be the beneficial owner of the Subject Shares.

As of the date hereof, none of the Reporting Persons own any Common Shares other than the
Subject Shares covered in this Statement.

Item 5(c) of the Original 13D is amended and supplemented as follows:

(c)

Exhibit 99.1 to Amendment No. 15, which is
incorporated by reference into this Item 5(c) as if restated in full, describes all of the transactions in Common Shares and options or other derivatives relating to Common Shares that were effected in the past 60 days.

Item 7. Material to be Filed as Exhibits.

Exhibit		Description
99.1		Trading data

5

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SIGNATURES

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.

Dated: April 22, 2016

6

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EXHIBIT INDEX

Exhibit		Description
99.1		Trading data

7