Alco and GP interiors

This is a rudimentary interior and seats for engineers.

Requirements.
This is for the sheet metal base with the vertically mounted light. The Horizontal mounted light will not work. It will not work if a horn is installed, the Horn Relay takes up the cab room.
A standard window for the Alco must be installed. This interior is made to work and align with the window in place.
An LED light is needed. Since this is close to the light and keeps the heat in one area, it may cause melting of the cab or interior.

Design Considerations

This is designed to be part of the assembly without glue or tape. It can be taped or glued if you desire.
The side height stops at the bottom of the window shell.
The width fits snuggly in the shell.
The front loop goes around the lightbulb base. This and the fit in the shell positions the interior.
There is a groove in the bottom to allow the light bulb wire to pass underneath.
The seat height was set to position an O scale seated figure. Figures vary so height may need to be adjusted.
The three Gauge holes allow light in to better illuminate the engineer. A decal could be placed over them if desired.
Supports are used to stiffen the back wall.

This is for the sheet metal base with the horizontally mounted light. It will not work if the original horn is installed, the Horn Relay takes up the cab room.
A standard window for the alco must be installed. This interior aligns with the window in place.
An LED light is needed. Since this is close to the light and keeps the heat in one area, incandescent bulbs may cause melting of the cab or interior. You may wish to add Aluminum Foil as a reflector to increase the effect of the LED light.

Design Considerations

The side height stops at the bottom of the window shell.
The width fits snuggly in the shell.
There is a groove in the bottom to allow the light bulb wire to pass underneath.
The seat height was set to position an O scale seated figure. Figures vary so height may need to be adjusted.
The 2 Gauge holes allow light in to better illuminate the engineer. A decal could be placed over them if desired.
Supports are used to stiffen the back wall.

There are 2 small locating slots on the bottom that fit the notch in the engine. If it moves too far forward, Hot Glue or similar may be used here to glue in if desired. 2nd picture below.

The light wire may need to be replaced or lengthened if the original is too short and gets in the way of the interior. If original wiring, it’s age may cause the insulation to crack if moved and most likely needs to be replaced.
This version can also be used if the light is vertical. Hot Gluing is recommended with the vertical light.

3D printing
I did this in .3 mm layers using PLA. A light color is recommended if you want to see any details or better reflect the light. .2mm layers with quality positioning should make smoother walls if desired. Printed with the bottom on the printing sheet. Supports are needed for the bottom and the cutout notch. Be careful removing the supports and don’t cut or break the 2 small locating notches.

A light is needed if you want to see the interior well. This will require adding a pickup. The MPC dummy did not come with lights or pickups. The mounting and screw holes are in the truck for a pickup. The frame has a wire slot near the rear truck. I recommend LED lights. The GP9 does have large exhaust holes front and back so heat buildup may not be a problem with incandescent bulbs.

Lionel Parts needed for adding a collector.

2328-170X Black Plastic Collector Insulator
2328-171 collector plate assembly
2332-109 insulating washer
6 x 5/16 slotted, round head self-tapping screw to mount it to the truck.

Design Considerations

The side height stops at the bottom of the window shell. The window may need slight cleanup of sprues and burs.
The front and back walls go to the top of the shell or window.
The width fits in the shell.
There is a groove in the bottom to allow the light power wire to pass underneath as needed. It is offset to keep the wire from rubbing on the truck mounting pin.
The seat height was set to position an O scale seated figure. Figures vary so height may need to be adjusted.
The 2 large holes allow light from an added headlight or LED to better illuminate the engineers and interior. LED lights could be added at the holes to illuminate the interior also.
Supports are used to stiffen the front and back wall.

Aluminum foil is added to help reflect the light when a light source is used. Figures are purchased O scale figures.

Interior installed along with optional LED lighting listed below.

3D printing
I did this in .3 mm layers using PLA. A light color is recommended if you want to see any details or better reflect the light. Paint as desired. Fine details such as control levers can be made from pins if desired.
.2mm layers with quality positioning should make smoother walls if desired. I used Hilbert Curve for the top layer to give it an anti-skid look. If you want a smooth top surface, Ironing will be required. Printed with the bottom on the printing sheet. Supports are needed for the bottom wire channel and the 2 holes. A slicer with Organic supports works well.

Included in these files are a GP9-lightmast.stl and .stp. This is an optional way to mount LED lights for the MPC era GP7/GP9 dummy. A self-tapping screw is needed to mount the light mast.

This mount is designed to follow the contour of the GP7/9. It can also be reversed so the LED lights shine directly forward.

Mounted in the GP9 with LEDs attached. 2 LEDs illuminate the interior. The second picture also shows the mounting screw has a solder lug attached. This is needed for Grounding the lights or power supply.

In my case I used a power supply to drive the LED lights, even though they are rated for 18V AC. This allows constant lighting across switches and other interruptions. It also allows me to adjust the voltage to the LEDs and control the brightness.

Postwar Alco and Modern GP7/9 Interiors