Text 1 Mechanically Refrigerated Wagons.

The most characteristic example of specialized wagons for carrying special types of freight is that of mechanically refrigerated wagons intended for carrying frozen goods. Such wagons, when there are a sufficiently large number of them, can replace refrigerator wagons for carrying foodstuffs.

The temperature controlled range of wagons includes both those with the cooling and the thermal systems for such cases when the temperature has to be raised instead of requiring refrigeration. Canadian Railways have at their disposal controlled temperature cars which maintain temperature accurately from below zero up to +75⁰ C. These perfect cars are intended for frozen food and dressed meat. Controlled air circulation virtually eliminates dehydration; they have wide doors for fork lift access.

Mechanically cooled vehicles, built at German plants, are designed for European climatic conditions, with ambient temperatures, ranging between +40⁰ C and -30⁰ C, and even these temperatures may be exceeded daily for a period of four of five hours. Transport of perishables calls for four ranges of temperature in the load space: -18⁰ C to -20⁰ C for transporting quick-frozen meat, fat, fruit or vegetables; -10⁰ C for transporting pre-cooled meat, fruit or vegetables; +2⁰ C for transporting fresh fruit or vegetables the temperature of which is up to 30⁰ C when loaded, so that within about 60 hours the goods are cooled down to +2⁰ C; and +12⁰ C for transporting goods which are susceptible to cold and must be protected from sub-zero ambient temperatures.

The four axle wagon with a capacity of 64m³ may be used as refrigerator wagon for journeys, lasting several days; and its continuous work at the extreme ambient and internal temperatures can be maintained for 120 hours. They are fully automatic in operation and do not need any maintenance and supervision. Before starting the temperature of the load space is adjusted, and automatic temperature control in each wagon maintains this temperature within narrow limits even if the variation of ambient temperature is such that changing from refrigeration to heating is required on the way.

The two refrigerating units of a four axle wagon are mounted just below roof level at both ends of the load space. They are accessible from the outside and raised platforms are provided for maintenance staff.

Text 2 Ventilated wagons.

It has been noticed for a long time that in the case of vegetables and fruit, the temperature is increased not only due to outside factors, but to the biological processes which occur in these vegetables after they have been harvested.

Aerated or ventilated wagons have openings sited in different positions in such a way as to allow air to circulate through the goods either by external ventilation or by the convection of the air itself.

These wagons have the advantage that their specialization, which technically is limited, also makes them suitable for carrying other goods normally loaded in ordinary covered wagons.

Text 3 Open wagons.

These wagons are intended above all to reduce the run empty mileage, and their specialization aims at offering the advantages of various types of wagons.

The open wagons combine the advantages of wide openings of open wagons and the protection given to the freight which is the characteristic of covered wagons.

For example, it if possible to design large openings on a covered wagon closed by shutters to allow room for loading and unloading palletized goods. A subsequent development was to make all the sides completely sliding, dividing them into several portions, to enable bulky units, which have to be transported protected from the weather, to be loaded easily. Openings can also be made in the roof and sides at the same time, but the most highly developed solution merely allows the whole roof to open.

In this case, starting with a covered wagon, it is possible to make its roof moveable, or to add a sliding roof of the traditional wagon sheets to a high-sided open wagon.