Cylindrical Grain Car Project Update - Part 1

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The new project for the summer of 2004 was a
Hawker Siddneley Canada Ltd. 4550 Cubic Foot Hopper car project

The drawings were started back on January of this year. The plans that I used were from Mainline Modeler magazine. I don’t have the magazine issue date at this time. I will try and include that information later if I can find it. I tracked down several cars and took many detail shots for future reference.

Auto Cad is a real help with this type of project. Anything that has curved metal parts is always hard to build. I started out by plotting out a full size copy of the cross section view of the car. I then rolled a section of steel to the proper radius and bent it in the brake to make a test part.

I laid the test part on the full size drawing to make sure it matched.
Having done that successfully, I then ordered the steel rolled from the sheet metal shop. Due to the length of their rollers, each car had to be made in two parts and assembled together later.

To make sure the bends were in the correct place to get the pear shape of the car, I printed out lines on a paper of the correct spacing and glued them to the under side of the cylinders.

The next step was to build a press that could put the bends in the cylinder so that each bend would be exactly alike. This is very important as the two halves have to match.

The press and the bending turned out to be a project in itself. Even though I am using 18 gauge material, it takes several tons of pressure to put that little crease in the material.

The first test part bent the 8” channel enough that the center of the part did not crease. Going back to the welder I added an “A” frame structure with a ¾” bolt welded vertically for adjustment. I did the same on the bottom. Now I can adjust the press top and bottom to withstand the force needed to make the bends match for the total length. (see photo of bender with part in place)

In these photos you will see the bent parts laid out on the work bench. Also in that photo you will note the side rails. Again this was a project that I did not have the equipment for. I made the drawings and Mike at the sheet metal shop formed on the press brake. This gives the car the added appearance of detail that I strive for.

As a side note: the ends of the cars are slanted. To cut this slant in the flat material before it is rolled is not just a straight cut from the middle. This cut is actually an ellipse. Mike approximated the cut line using a steel ruler and bending it. As it turned out, his cut just needs a little filing to be right on the money.

The next step was to make bulk heads to shape the car and keep the tube from twisting. Again thanks to computers this job was made accurate by gluing the full size drawing to a piece of 1/8” steel and running it through the band saw.

The next step was to build a fixture that fit into the vise on the CNC mill and true up all the edges making sure all the parts were identical.

The center bulkheads will be welded into the tank and the two halves will be bolted together to avoid welding on the outside of the car. These holes were also put in using the CNC mill for accuracy.

All this work could be done with basic tools, band saw, grinder, files and drills. It would just be more labor intensive and take longer. Don’t be discouraged by the use of the CNC and Auto cad. They are just helpers.

The outside ends of the car have an oval shaped hole that has to be cut. That hole was cut before anything is welded together.

The next part has to be done very accurately. I went around the outside walls with cargo straps and squeezed the bulkheads in place for welding. I had pre welded some small angle pieces on the bulkheads to help keep them from slipping around. Make sure you don’t weld a bulkhead over where a hole for the hatch may be later.

Here the steel shell with dividers is being pulled together with clamping straps.

Section laying on floor clamped together and ready for additional welding.

Here we have all three sections almost in place. Three quarter inch
thick plywood bulkheads were used to keep metal plates from slipping
sideways when belts were tighten around the forms. Plywood was removed
after welding was complete.

Here are the two sections of the cylindrical hopper bolted together.

Holes drilled in side for plug welding side braces on.

Side rail are now being attached to the two
bolted together sections.

Side rails welded on and car primed to resist rust.

Part 2 >>