Scale-Craft freight trucks are a standard in OO. The first die-cast truck produced in OO, they were introduced in 1937 and are the most common type seen. While pretty reliable today (unless the bolster has shrunk–some have over time–and they are not especially free-rolling unless well adjusted) these by modern standards do have a bit of a toy like look.

Most firms in the period tried to make their trucks more realistic, but two other companies also produced very similar trucks. These photos are side and bottom views of all three of these trucks. On the left is a Famoco/Eastern truck, in the center a Scale-Craft truck, and on the right the original version of the Graceline truck. At a glance they all look the same, from the side

The Famoco/Eastern truck from the side is quite similar but with a shorter wheelbase. It clearly is a close copy. In the top and bottom views however it can be seen that they used a different style of bolster, one of cast metal that was crimped on. Also the wheelsets are of a more standard design with a full axle.

The other truck, on the right, is Graceline. They made a number of types of trucks; this is what I take to be the first type. The wheelbase is slightly longer and the detail less fine. Note that the bolster is a block of fiber material with pins that hold the sideframes on. Also, look at the axles. They are of the same type as Scale-Craft, with half axels that are joined by a Bakelite tube. The tube is larger diameter than Scale-Craft and the flanges are less fine as well.

Both of these I believe were intended to be better/cheaper trucks. They do have fewer parts and must have been cheaper to make. In practice I find the Famoco/Eastern trucks can give decent service on the layout if they have a good set of wheels and the Graceline version can be made to work with a good set of wheels also. I have seen Graceline trucks with quite a variety of wheelsets, actually–a post for another day.