In the Late Sixties CPR used their 12 Wheel Passenger Container Flats on Trains 42 and 41 I think they were, East from Montreal to the Maritimes, and Yes! these Trains Handeled FISH!
At Windsor Station CP would Handle the Fish Cars with CP 7034 or CP 7041, Alco GE S2s, and we would sometimes get a Ride on the Engine and ‘Noticed’ the Fish Right away.
Oils Dripping from the Fish Cars would Coat the Rails in the Fish Spur, giving the Wheel Slip Buzzer on the Alcos a Work Out!
The CP Maritimes Trains were once Powered by CP’s MLW 244 FPA/B2s and S/G ‘Passenger’ RS10s, as the Train never got going Fast Enough to Require Units with Passenger Gearing. Severe Grades on the way to the International of Maine Division.
The Eastbound Train would be at Montreal West around the same time as the D&H Train to New York City which had Alco Passenger RS2s, then the PAs ex ATSF.
Later on the D&H would sometimes get an EL E8 such as 822.
Now, for Tender Flats.
Steel Mills ALWAYS had Kit Bashed Cars ( and Locomotives ) made from Candidates that Arrived by Rail for the Steel Furnaces.
Stelco at Hamilton, Ontario had a Fascinating Rail Operation with their Own Locomotives, Steam and Diesel, and they Constructed Heavy Duty Flats from 12 Wheel Locomotive Tenders as per this Link.
Scroll Down and Click on Stelco’s Railway
http://www.trainweb.org/oldtimetrains/articles.html
And Cut Up Steam Locomotives from NYC, C&O, TH&B, and I Assume, both, CP and CN.
http://www.trainweb.org/oldtimetrains/stelco/nychudson.htm
http://www.trainweb.org/oldtimetrains/stelco/CO2808.jpg
( Looks like they were Planning a 4-10-4? )
As can be seen in the Main Article, Stelco Cut Up Ships including the 'Noronic