Just as an addition to all of the above info, My dad worked for the MDT somewhere around 1929 + as an ice inspector for them. He worked out of Rochester, then to Bellefontaine, Ohio where I was born, then on to the yards at Toledo Ohio. I used to accompany him to the ice house where he made sure that the correct amount of ice and salt were added to the end part of the car before it took off to other stops along the way to its final destination. Many memories are with me to this day.

Ice was used so the floors were raised in the middle to allow the melted ice to run off. They stayed raised even after loading.

if they have that new-boxcar smell?

Despatch is now called East Rochester. Merchants Despatch Transportation Company churned out thousands of refrigerated rail cars (among other types) for over a century in this spot. The car shops closed in 1970.

The freight cars are touting their air brake system, which was pretty modern for that time. The brake hose hanging off the back of the rear car is referred to as a "Glad hand" and is identical to those we use today.

[George Westinghouse invented the air brake in 1869. - Dave]

It's interesting that in this shot you can see that the cars, when new and empty, rose up in the middle so the floors were flat once they were loaded.

Those cars still look brand new and are coupled together in order of their registration numbers, so it seems they come directly from the manufacturer. The date of the photograph was probably not too far from the date of their commissioning painted onto the cars (5-12-1904).