For this article, I am just going to build a single, open half-door on each side, as that is how the car is run most of the time.  This requires a good, sharp blade, some patience and skill, and bit of high-quality masking tape.  First things first: remove the combined roof/glass by squeezing the tabs under the floor and pulling the roof off the car at the same time.  At this time, I also remove the Rivarossi trucks and “whale harpoons” that are used as couplers so that I can replace them with Walthers trucks and body-mounted Kadee couplers. 

The opening for a half-door is cut just below the window frame on the baggage door.  (See Figure 4.)  To do this, I tape across the door right below the window, giving me a straight line to mark my cut with.  I use many repeated strokes of the knife – not bearing down too hard – to cut through the plastic at this area, and then I repeat the cut on the top of the door and along the sides to open it up.  After the top half of the door is removed, file the rough edges smooth with a high-quality file.  (I have found that the cheap nail files from your local big box stores, such as Walmart, actually are nice for this type application; instead of going to the hobby shop and spending $8 to $10 on each file, you can go the big box store and get nail files for about $2.)  Repeat the process on the other side of the car.

Now that you have the half-doors opened up, you must cut the corresponding door glass from the roof; these also are multi-pass, scribe-type cuts.  Once the doors and windows are cut, it is time to add the armrests in the doors.  I use .040" styrene sheet to make them, cut them 4mm wide and 13mm long; then, I file the piece shorter to fit the door opening (this comes to about 12.5mm when finished).  I spray these gloss black and set them aside until the car is painted. 

As the original trucks and couplers on these cars are “train set quality,” they should be replaced.  For the trucks, I use Walthers GSC 41-NDO, outside-swing, 4-wheel passenger trucks (part #920-2101).  To mount them, I use Walthers truck mount adapters (part #920-2310) with a long screw, a washer, and a nut on the inside, much the same fashion that brass cars have their trucks mounted.  I also body-mount Kadee #5 boxes and couplers with 2-56 screws holding the boxes in place.  I use the old Roundhouse metal coupler box covers between the car floor and the coupler box so that the box is flush-mounted at the correct height. After the trucks and couplers are mounted, I add weight to the car to improve reliability; I do this with 1/4 oz., stick-on tire weights that you can get from most auto parts stores.  I add 10 weights (a total of 2.5 oz.) to bring the car up to a reasonable weight of 5.75 oz.  (See Figure 5.)

This is the point where good quality masking tape comes in handy.  If you started with a UP car, then you can skip this step; just glue in your armrests, add passengers inside the open doors and reattach the roof to the car.  But if you are like me, you had to strip off a different paint scheme and now need to repaint the car. The ends and bottom of your UP car will be Harbor Mist gray.  When I paint these cars – or any car, for that matter – I always paint the lighter color first; in this case, that means the yellow goes on before the gray, I use Scalecoat paint on all my builds, but you can use whatever paint you are comfortable with.  I airbrush the paint, but you can use a spray can, instead.  

After the paint is dry, it is time to add the armrests and people to the car; you want the armrests mounted flush with the surface of the car side.  After they are fixed in place, add your passengers and install the roof. (See Figure 6.)

Once the roof is in place, it is time to decal the car.  I use Microscale decals for the Union Pacific Lettering and red stripes.  Depending on which car name you are going to add to the side, use either the Microscale UP Business Car decal sheet or the UP Car Name sheet from Circus City Decals.  The final details include adding diaphragms to the car ends and a firecracker antenna on the roof. (See Figure 7.)  All that’s left now is to add this great car to your excursion fleet and enjoy those waving people in the half-doors, as UP locomotive #844, #3985, or #4014 slugs away up front.  Check out this video to see this and other custom cars rolling by in a UP consist.