To paraphrase Vane Jones, "Knowledge is of little value until shared with others."

Sunday, January 4, 2015

Finishing a Q-Car CRT 4000 Plushie Part 1: Installing the Power/Trail Trucks

With the New Year, a new model which includes a power truck installed above the floor. Hope you will enjoy it as much as I have.

Before starting any model always find as many prototype photos of the model you wish to build. These should be of the specific car number and date of operation to match you model. Examining the photos of the CRT 4000 series of cars, specifically the "Plushies", you'll find many different variations of details. Build to the photo!

Before going further you need to obtain:
  1. Shore Line Interurban Historical Society Dispatch Number 5, "The Chicago "L's" Great Steel Fleet ~The Baldies~"
  2. CERA Bulletin B-113 "Chicago's Rapid Transit Volume I: Rolling Stock 1892-1947"
  3. CERA Bulletin B-131 "The “L” The Development of Chicago's Rapid Transit System, 1888-1932".
These publications will give you a chance to see photos of the 4000's during their many years of operation. Many of your questions about the 4000's will be answered. Just in case you are 1st finding out about the CRT/CTA 4000 series of cars, they can be broken into two different types called "Baldies" and "Plushies". The publications listed above will explain the names and the differences between the 2 names.

I had the opportunity to ride both the "Baldies" and "Plushies" for the 4 years I was going to high school. This gave me the opportunity to examine the prototype cars and their details.

Almost all of my "L" models are representative (built and painted) of the months just before the take over of the "L" by the Chicago Transit Authority (CTA) from the Chicago Rapid Transit Company (CRT) - October 1,1947. My model will be made for this era.

I like the pre-CTA era since during this time the CRT still ran its equipment in many unique ways. The Q-Car CRT 4000 "Plushie" is patterned after the prototype cars of the 1940's.

Start by inspecting your model for completeness and lack of problems (broken items etc.). Q-Car has stopped making epoxy bodies. Correcting problems with the body may be troublesome but can be done. Some of the roof boards had come loose on my model. They were reattached using CA.

If you have a used painted 4000 epoxy body from which you wish to remove the paint, a friend of mine who has removed paint from a Q-Car epoxy body has been asked to write what he did to remove the paint. When his information is available his experience will be posted.

Since the power truck is heavier than the trail truck, it's best to install the trail truck 1st at the correct location and height. This will make it easier to secure the power truck at the correct height. On the prototype 4000 both the power and trail trucks are centered on the floor.

The bottom of model's wood floor is level with the model's sides and ends. This makes it easy to set the height of the floor with relation to the trail truck sitting on level track. The bottom of the prototype's floor is 3'2" above the rail. Therefore the bottom of the model's floor has to be a scale 3'2" above the rail head.

With the floor in place on the model, mark the center line (half way point) of the floor on the bottom of the floor from end to end. Then from the outside of the car's sides mark the center line of the floor . Draw the line from screw to screw. Inspect the model and decide which end is to be #1, motor, end. Mark both the floor and body with #1.

Any measurements for the centerlines must to be taken from the outsides of the sides and ends of the model. Wall thicknesses of the side and end castings can vary. Also, there are prototype trolleys where the distances from the end of the car to the truck center points are not the same!

Unscrew the floor and remove the floor. Place the 2 screws plus the body in a safe secure location. Notice the screws are 2-56 flat head. The truck centers are a scale 33'8". Using the floor's center point mark the locations of the truck centers. Then, with a sharp, hobby awl make drill starter holes in the wooden floor at the truck center points. Use a #40 drill to drill through the wooden floor.

Side Bar Note - If the truck centers are shortened, i.e., 33'0" instead of 33'8", the car will turn on shorter radius curves but will have additional overhang. Sometimes a shorter truck center is required to clear steps and other items on the underbody at the end of a model. 

Example of a sharp, hobby awl. The darkened end is the result of stirring paint.

My sharp, hobby awl was obtained 50+ years ago as part of a dissecting kit for a college zoology class. The correct name is a pithing needle or tissue teaser. It is the inexpensive form - a piece if strong steel wire sharpened to a point inserted and glued into a wooden handle. From time to time the point has to be sharpened.

You can make one from 0.050" - 0.060" or 1/16" piano or similar wire cut to 2-5/8" in length. The handle is 0.250" or 1/4" wooden dowel about 4" long. Drill a hole about 1" deep for the piano wire to be inserted into the wooden dowel. Make the hole slightly oversize.

Use medium setting CA fill the hole about 25% and insert the piece of music wire. Allow the CA to completely set for 24 hours. Using a grinding wheel taper the outer 1" of the music wire to a point. Do not get the wire red hot as the temper of the metal will be lost. If this does happen you will have to start all over again.

If possible coat the wooden handle with some sort of clear finishing lacquer. This tool has many uses including making a centering hole, punching holes through 0.005" brass sheet, holding parts in place while CA sets, and more.

To find the correct floor height, scale 3'2" above rail to bottom of floor, start mounting the trail truck by enlarging the #40 truck center hole to clear a 3-48 screw. Attach the body bolster provided to the truck. Place the truck in its  correct location. Do not use any glue yet. Holding everything in your hands place the floor and trail truck on a small section of track.

Using scraps of wood or styrene strips under the floor at the power truck end, level the floor. With a ruler check to see if the bottom of the floor is a scale 3'2" above the top of the rail. If it is not, take appropriate measures. This may include altering or replacing the cast metal body bolster supplied with the truck.

For my model the body bolster was replaced with apiece of 0.125" styrene 1-1/2" long and 0.500" wide (Two pieces 0.250" wide.). A hole was made and taped for a 3-48 screw. Using a 3-48 screw to locate the truck center hole, CA the new body bolster to the bottom of the floor.
 This is the new body bolster CA'ed to the floor.

Here the trail truck is screwed to the new body bolster. Notice the spring over the truck mounting screw. PSC #350 springs work very well. The screw is screwed in far enough for the head of the screw to clear a toothpick placed over the bottom center of the sideframes. a 3/4" long 3-48 screw is used. Normally a 1/2" long 3-48 screw is provided by the truck manufacturers.
The use of a spring with non-powered trucks keeps the truck snug up against the bolster to prevent wobbles. Only 1 truck of a model has to be treated this way. The other benefit is the grounding of the truck against the bolster helps with the return current to the rails or, in the case of a 2-rail model, the return of the electricity to the selected rail.

Once the CA has set install the trail truck. Place the floor on a level work surface. Place the power truck under the floor. Is the floor level? Is it too low on one end or the other? If the floor is too high on the power truck side, like mine, the power truck has to be attached either in the floor or above the floor.

As can be seen the floor is not level. A screw's head can be seen in the photo. The base of the truck's bolster is just to the inside of this screw head.

Cut a hole in the floor large enough for the width of the power truck bolster at it's base and long enough for the length of the motor. See the photo below. Notice the pencil lines on the brown colored primer. All measurements are taken from the truck center point hole in the floor. I forgot to mention, this is the bottom of the floor.

The additional box drawn on the left is to clear the gear box which will be cut into the floor if needed. The larger rectangle has to be cut out 1st.

The power truck is inserted in the hole in the floor. Notice the body bolster, the piece of flat brass strip held in place with a grommet onto the truck bolster, is too wide. It has to be cut shorter on both ends.

The amount of brass to be cut off is how much the brass strip extends over the sides of the floor plus the width of the epoxy ridge inside the model's body at floor level.

This photo shows the 2 scratches in the brass where it needs to be cut.

The 2 mounting holes, seen above, were cut off. New mounting holes in the center line of the brass strip were drilled to clear a 1-72 screw. How far the holes are from the edge of the brass are depended upon how much wood is available to hold the screw securely.

Since you are working from the bottom of the floor some judicious measuring needs to be done. I did the measuring and hole drilling, then the power truck was mounted on the floor using self tapping screws. Once the floor is set flat on a level surface, is the floor level? This will tell you if the power truck has to be raised or lowered more.

The body bolster of my power truck needed to be raised above the level of the floor. Using small pieces of styrene and 1-72 screws; the floor was leveled. The work looks sloppy in this trail fitting. Correct size styrene pieces will be made for the final installation.

Notice the area to the left has been cut out to make way for the gear box. This is a measure, cut, and fit type of job. Work at it slowly.

The final mounting includes round head screws on top with washers and nuts on the bottom. The order of the head, washer, and nut can be reversed. Where ever there is wood always back up the nut or head of the screw with a washer to prevent breaking through the wood.
Blue arrows = The floor was cut out to clear the gear box.
Red arrows = Where ACC was applied to the styrene blocks used to hold the truck bolster above the floor.
Green arrows = Where the floor was cut back to clear the wires to the brushes and their holders.
Maroon arrows = More cut out to further clear the motor's magnet.
Notice the hole in the floor is purposefully kept small. It's just large enough for the swing and operation of the truck. The other reasons are to keep the area available for an interior and for the potential addition of lighting in the model. More on the latter reasons as the model is finished.
Here is the model, the body on the floor, on the test track. Does it look level? When measured with a ruler it is!

Next is the adding of the underbody parts to the floor and work on the epoxy body

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