SWAMP CREEK & WESTERN
RAILROAD ASSOCIATION

211 Railroad Ave. Edmonds, WA 98020

LAYOUT ELECTRICAL MANUAL

Established December 5, 2000

Revised by page

VII. BLOCK POWER SELECTORS

VII. BLOCK POWER SELECTORS:

The DC track power is distributed to all control points on the layout via the cab power buss. See Section V.G.

Corresponding color-coded wires (Green cab, Red cab, etc.) feed the selectors with the positive side for each mainline cab or other local (branch, yard) power. See Section I.C.2. for other power buss color codes.

A.   Mainline Selectors:

The block selectors used on the mainline are a rotary type: single pole, 12 position switch. They provide the operator with each of the various mainline cab choices and "off" positions. In some locations yard and branch cabs are also available as noted below.

B.   Yard Selectors:

The block selectors used on the yards are a rotary type: single pole, 12 position switch. They provide the operator with each of the various mainline cab choices plus local yard cab selections and "off" positions. See Section VII.F below for operation.

C.   Branch Line Selectors:

Tumwater Mining and Cascade Timber Co. branches will use single pole, single throw (SPST) on/off switches as they are single cab operations. The exchange track sections will be controlled with single pole, 12 position rotary switches and provide the operator with both the branch line cab control or any of the mainline cab choices.

D.   Block Control Terminal Strips:

The mainline power buss is connected through standard 10 bar screw-type terminal strips mounted near each control point. More than one selectors may be attached but they should not be overloaded.

In all cases the wires are to be connected with proper-sized crimp-type solderless connectors.

Cab color-coded wires (Green cab, Red cab, etc.) feed the selectors with the positive side for each mainline cab, or other local (branch, yard) power. These are soldered to the individual tabs of the rotary switch.

The center tab of the rotary switch is connected back to the terminal strip with a Yellow wire.

The positive rail (+) is feed from this point on the terminal bar with a YELLOW wire. (Branchlines, etc. may be a different color. See Section I.C.2.)

The negative rail (-) is connected to the common return with a BLUE wire.

The common return on the power buss is the WHITE wire.

Keep in mind the plus side of the power to the track is set up with the old West Coast practices (1945-1960) of Engineer's right, (right side) heading **west** from Orchard's mainline at the passenger station (negative will be the rail closest to you at this point, then follow it around the layout, noting that as the track turns back around along the back wall, the negative rail will be away from you at all other locations on the layout.)

So the rule is: positive (+) on right, westbound.

In most cases, except at ORCHARD and WAITSBURG return loop where the tracks loop around on us, the positive YELLOW wire will be towards the isle, and the negative BLUE wire will be away.

The tail sections of the return loops are wired through bridge rectifier are another exception. They must be isolated. See Section IX.C.

E.   E-W Yard Toggles:

Rather than using Cab selectors for each track East - West toggles are employed in Orchard Yard and Willow Grove Yard thus simplifying the wiring. Cab selectors "towers" are located at both ends (east and west) of the yards. They feed the power, via three position (center off) toggle switches, to each yard track. (The ladder tracks are power routed out.) Thus any single or multiple tracks can be thrown to either tower for control.

The positive side of each track (+) is brought to the center tab of its respective toggle using 18 gauge stranded YELLOW wire. The same type wire then connects from the outer tabs to the east and west selectors respectively. The toggles are connected in series.

The negative side is common and connected to the common return on the power buss which is the WHITE wire.

F.   Local Off/On Toggles:

Engine pockets and some spurs are electrically isolated so locomotives and trains can be turned off from the rest of the block. In these cased the positive rail (+) will be gapped and insulated, and feed through a SPST toggle using YELLOW wire.

G.   Catenary - Electric Overhead Wiring:

Since the overhead wiring is not electrically isolated into blocks it cannot be operated with the separate selectors. It is hard wired to the Tumwater Mining branch cab via an on/off SPST toggle.

SWAMP CREEK & WESTERN
RAILROAD ASSOCIATION

211 Railroad Ave. Edmonds, WA 98020