Following from my Car Service Division records concerning handling of Canadian ownership equipment.
"Special Car Order 36 issued in 1938 and broadened by later amendments suspends operation of Car Service Rule 2 as to Canadian National and Canadian Pacific box cars received from western lines and released on certain eastern roads connecting with the CN and CP at junctions east of Lake Michigan so that such cars may be returned in home route to the Canadian lines at western interchange points." This from 1945 Car Service Division reports.
Code of Federal Regulations Title 19 1945 (Customs duty 317, later part 123) governed the use of Canadian equipment. "On return trip....other equipment may be used in such trains or for such local traffic as is reasonably incidental to its economical and prompt return to the country from whence it entered the United States".
Once unloaded in US, Canadian cars were handled in accordance with Rule 2 or Rule 3 of Car Service Rules depending on its location and were treated the same as a US owned car. At various times between 1940 and 1960 different Car Service Division "requests" and ICC "Service Orders" applied, normally with specific time limits.
June 14, 1946 Car Service Division "Mailgram" issued to US transportation officiers: "Canadian cars may only be loaded to or substantially in the direction of home and that they should not be delayed excessively while held for prospective loading".
Sept 22, 1947 Car Service Division "Circular" issued: "Requesting railroads to stop the misuse of Canadian boxcars account over 8,000 excess cars in US.
The "Circular" apparently did not hold enough "force".
ICC issued "Service Order No. 784 effective from Oct 23, 1947 until Nov. 30, 1947 requiring all US railroads shall send home empty at once all boxcars of Canadian ownership".
It should be noted, ICC "Service Orders" were legal and binding and had the authority of law. Fines could be assessed for non-compliance.
Car Service Directives, Mailgrams, Circulars and Special Orders were not mandatory. There were NO fines for non-compliance.
Outside the scope of the group, CSD's and Special Orders become "Force of law on Oct 1, 1971". After this date non-compliance allow fines to be assessed.