C, Construction Steps
Model 106 Single Track Block

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Sections shown below on this page:

1. Summary
2. Wiring Color Code
3. Obtaining Colored Wire
4. The Laminated, Modular Design
5. Making Template and Bases
6. Attaching Parts - Control Unit
7. Connect Wires - Control Unit
8. Assembly Steps - Track Unit

1. Summary

This section outlines the steps required to construct, in four phases; and then operate a G-scale model railroad control device, referred to as an "Model 146b Automatic Block". This Automatic Block automatically controls two trains (sometimes more) on the same track, by keeping them separated from each other by maintaining a predetermined spacing.

Figure 1 - Model 146b Single-Track Experimenter's Block

2. Wiring Color Code

To make it easier to follow the paths of the circuits on the templates, all the wires are color-coded, as per the following figure.

Each drawing has the wire numbers and colors listed. If you are using the black and white drawings in this bulletin, I recommend you use a colored pencil to color the wires on the template. The circuits are 10 times easier to follow after the wires are colored.

Figure 2 -Wiring Color Codes

3. Obtaining Colored Wire

I recommend using solid, 18 gauge colored wire to construct the control unit. Some people use stranded wire and non-colored wire for the control unit, but I advise taking this shortcut. The solid wire you can shape better to follow the paths, and the colors make it much easier to understand how the circuits work.

I also prefer the solid wire because it easily screws to the 17000 track contacts and 10153 isolating track terminals, versus having to put the 50131 press cable connectors on the ends of the stranded wire.

You can get the 18 ga solid black, green, and red wire from Radio Shack. The 18 gauge solid blue, yellow, and gray colors is not available from Radio Shack, but is still considered a common product. Two manufacturers that make these colors are Carol Cable and Apex wire. See parts list on page 36 for the part numbers.

You might be able to find a distributor close to you by calling these wire companies' headquarters. Carol Cable has several numbers, in Manchester NH at 800-424-5666, and on the west coast 800-372-6374. Apex Wire is in Hauppauge, New York, and their phone number is 516-273-3322.

A distributor here in Denver named Cashway Electric at 303-623-0151 (use the All-Wire part number) handles the Apex wire, and they told me they can ship it to out-of-town customers.

For "runs" of longer than 30 feet (connecting to the track), you may want to consider using a heavier wire.

4. The Laminated, Modular Design

What's A "Laminated Template"?
The control unit for this block is built on, what I refer to, as a "laminated template", as shown in the following figure.

Figure 3 - Laminated Template For Control Unit
The laminated template is a full size drawing, with all the wires shown in the proper color, that has been plastic laminated. You glue the laminated template to the wood base, and then attach the parts right on top of the template.

Using the template has the following advantages:

  • Assembly is easier, since you just attach parts and wires right on top of the outline on the template. There is no measuring or wondering where anything fits -- it's almost like a child's "connect the dots" coloring book.
  • More importantly, you have built-in documentation showing where every wire belongs and connects. The small diagram just above terminal block TB4 shows, in icon form, exactly how every wire connects to the track.

What's A "Modular Design"?

This unit uses a "modular design" -- that is, the control unit is build on a separate base from the track unit. Having the control unit separate from the track gives you flexibility. You can move the control unit to a location away from the track unit, such as in your control panel, or to a different track unit, or swap-out one control unit for another one having different components or logic.

What If I Skip The Template And The Modular Design?

You could save some steps by omitting the template and mounting parts directly on the track unit, but I would advise against this. The documentation of the template is always helpful., and having the control unit detachable from the track gives you flexibility.

== Construction Steps ==

5. Making Template and Bases

1. Procure all parts per the parts list Sheet 7. The drawing sheets are shown in the previous Section. The Item numbers refer to items on the parts list Sheet 7.)

NOTE: You do not need the first 3 items on the list for the Phase 1 version.

Making The Template

2. Enlarge the BOTTOM half of Sheet 9, Phase 2 Control Unit -- Standard Version w/Slowdown, to get it to the proper size.
  • Note the 1-inch square box on the left side, that you can use as a check that the size is correct.
  • NOTE: If you are using Item 4 Drawing Set for Automatic Block, you do not need to do Steps 2 through 5, since the template is already full-size, colored, and laminated, and ready to go.

    3. Identify the border, where you see the note "... cut along this line". This template border should be 3-3/4" wide and 15" long after enlargement to full size.

    NOTE: Double check that you are using the bottom of half of Sheet 9, and not the drawing on the top.

    4. Use blue, green, red, and yellow colored pencils to color the wires on the enlarged Phase 2. The note above motor M3 "Wiring Color Code" defines the color of each wire.

    5. Plastic laminate this 3-3/4" wide by 15" long colored sheet. 'Office Depot' type copy stores can do this laminating. Or you can buy do-it-yourself laminating sheets (such as C-Line #65001 Clear-Adheer Do-It-Yourself Laminating Sheets) from Sam's Club or office stores.

Base Assembly

6. Cut a piece of 1/2 inch thick plywood 4" wide x 21" long for the base of the control unit (Item 27).

7. Cut a piece of 1/2 inch thick plywood 12" wide x 26" long for the base of the track unit (Item 62).

8. Sandpaper the bases to remove all rough spots.

9. Paint the base using Ace 35A-1A Beechtree (Item 19, brown) or color of your choice.

10. Glue the laminated template (Item 13) to the rear end of the wood base, using the adhesive (Item 17). There should be about 1/8" border on 3 sides, with about 5-7/8" on the front -- refer to Sheet 4 Track Unit Assembly as a check.

NOTE: The directions left, right, front, rear; are as per coordinates shown on the drawings.

The base is now ready to attach parts.

6. Attaching Parts - Control Unit

Figure 4 - Model 146b Control Unit

Preparing Switch Motor M3

11. Preparing Switch Motor And Relay: The 12030 relay points (Item 12) snap into the end of the 12010 switch motors (Item 11). There is a plastic cover plate on the end of the motor. Pry this cover plate off using a screwdriver, and then snap the relay points into the end of the switch motor.

12. Ream the holes in left-rear and front-right feet of the switch motor with a 7/64" drill.

NOTE: As an alternate to screwing down the switch motor, if you don't want disturb the threads in the plastic feet, you can drill 9/64" holes in the wood base, and use wire to tie the plastic feet to the base.

Drilling Holes and Attaching Parts

13. Drill 5/64 pilot holes in the wood control unit base, for the knife switch, light bulb base, terminal block, and switch motor.

NOTE: You can later disconnect the light bulb, or omit it entirely, if you are planning to add signal lights.

The purpose of the light bulb is to verify the control is receiving AC power. The signal lights will verify presence of power also.

14. Screw these parts to the wood base by using #4 x 5/8" long wood screws (Item 29).

15. Holes for Wing Nuts and Screws: Drill two 3/16" holes in the base. These holes are for the screws and wing nuts used to attach the base to the track unit. Note the template shows you a set of crosshairs for the wing nut hole location at the right-rear end of the base.

  • Refer to Sheet 4 Track Unit Assembly for the location of the left-front hole, since it is off the template.

7. Connect Wires - Control Unit -- Phase 1

Note that we are using the template we made from the Phase 2 diagram, that we now have glued on the wood base. But we are using the Phase 1 diagram as a guide for the following steps.

In Phase 1 we will build a "bare bones" basic unit. Thus we will not use all the wires shown on the template for Phase 1. Later we can add the rheostat and additional wires to make the Phases 2, 3, and 4.

Construction Notes

  • You can strip about 1/4" of insulation off the ends of wires that connect to switch motors and relay points. -- that is, where you are sliding the end of the wire into the small hole.
  • When stripping insulation off the ends of wires that connect to terminals, you can strip off about 1/2".
  • When connecting wires to terminals, you can use the spade connectors (Item 51) to make a neater attachment.
  • You might want to experiment with the procedure of hooking up one end of the wire, then using pliers to bend sharp corners to follow the path on the template fairly exactly to achieve a neat installation -- depending on how fussy you want to be.

Attaching the Wires

Use Sheet 9, Phase 1 Control Unit -- Starter Version, as a guide for the following steps -- don't look at Phase 2 yet.

16. Black Wires: Connect BLACK wire L3 (prefix L=BLACK) using 18 gauge solid wire (Item 20).

Black wire is used for DC + that is "switched" -- that is, sometimes the power is on, and sometimes the power is off. (DC - on the right rail is not connected to the control unit at all.)

17. Blue Wires: Connect BLUE wires B2 and B99 (prefix B=BLUE) using 18 gauge solid wire (Item 21).

Blue wire is used for DC + that is "unswitched" -- that is, the power is always on.

18. Green Wires: Connect GREEN wire G2 (prefix G=GREEN) using 18 gauge solid wire (Item 23).

Green wire is used for AC + that is "switched" -- that is, the power is momentarily on if the corresponding track contact is activated, but is normally off.

19. Red Wires: Connect RED wires R2 and R11 (prefix R=RED) using 18 gauge solid wire (Item 24).

Note wire R3 is the wire coming from the light, Item 82. For this wire, you can just shorten the wire that comes attached to the light and use that.

Red wire is used for AC - (common).

20. Yellow Wires: Connect YELLOW wires Y1 and Y16 (prefix Y=YELLOW) using 18 gauge solid wire (Item 25).

Note wire Y3 is the wire coming from the light, Item 82. For this wire, you can just shorten the wire that comes attached to the light and use that.

Yellow wire is used for AC + that is "unswitched" -- that is, the power is always on.

Conclusion: At this point, the Phase 1 assembly of the control unit should be complete.

8. Assembly Steps - Track Unit

Figure 5 -- Model 146b Track Unit

Attach Track To Base

Refer to Sheet 4, Track Unit Assembly, for the following steps.

21. Position the loose track on top of the wood base.

22. Verify for both 10153's (Item 48), the gap is in the left rail

  • Verify you have not forgotten track contact T1.

    23. With the track in position, use a 5/64" drill to drill holes through the plastic ties and into the wood base.

    24. Attach the frontmost 2 pieces of track using #4 x 5/8" long wood screws (Item 29).

    Leave the rear 10153 single isolating track unattached. This can disconnected, moved to the rear, and more track inserted in-between, to make the length of the stop block as long as necessary.

Attach Control Unit to Track Unit

25. Position the control unit on the corner of the track unit, and drill two 3/16 holes to match the holes in the control unit.

26. Using the 2 wing nuts and screws (Item 28), attach the control unit to the track unit.

Connecting Wires On Track Unit

For the following steps, use a 9/64 drill to drill holes through the wood base as required, in order to run the wires underneath.

27. Black Wires: Connect BLACK wire 7.

NOTE: Black wire 3 does not get attached until later when you add the slowdown circuitry in Phase 2.

28. Blue Wires: Connect BLUE wire 8.

29. Green Wires: Connect GREEN wires 9 and (after reading below) 12.

30. Yellow Wires: Connect YELLOW wires 10 and (after reading below) wire 11.

Option: Use Stranded Wire For Wires 11 & 12

On Sheet 04, Track Unit Asembly, the two wires 11 and 12 are shown as yellow and green respectively. If T2 is going to be permanently located in one place, then use the solid yellow and green wire as described in the previous two steps, so you have the color coding.

However, if you plan to move track contact T2 a lot, you may want to use the stranded wire instead of solid wire. If you want to use stranded wire, substitute the following 2 steps for the previous 2 steps.

31. Using the double-conductor 18 gauge stranded wire (such as Radio Shack 278-1301 or similar), attach the darker conductor (substituting for green) to terminal 12 on the terminal block. Connect the other end to the front-most terminal of track contact T2.

32. Using the same double-conductor wire as the previous step, attach the lighter conductor (substituting for yellow) to terminal 11 on the terminal block. Connect the other end to the center terminal of track contact T2 as shown.

Connecting AC Power

Make sure you read the comments about voltage in Increasing AC Control Voltage in the previous section.

The power input is via terminals 17 and 18 on the center of the knife switch. Connect these to the AC terminals on your power pack.

OPTION: You can connect input power using a female RCA phono plug for a quick connection. This is shown in the following figure, Using Phono Jack Wire For Input AC Power.

You can use a Radio Shack #42-2449 or similar; and cut it into a piece about 1 foot long and a 2nd piece about 11 foot long. You can put spade terminals on the cut end of the 11-foot piece to connect to the transformer. The other end has a male phono plug, with a connector, will quickly connect to the male phono plug of the 1-foot piece connected to the control unit.

Figure 6 - Using Phono Jack Wire For Input AC Power

What To Do Next

At this point, you have completed the assembly of the bare-bones Phase1 block. The next section tells you how to operate this unit, plus instructions to add the additional parts to build Phases 2, 3 and 4.
This page created 8/2003, modified 5/5/2006 by (bottom include)
JamesRobertIngram.com , Williamsport Pa, Voice Mail 570-322-7597