Resource Information...

That I've accumulated referencing our hobby. More to come; submissions encouraged (send to oddsales@earthlink.net)

Draw Pull Chart -

For use with our DHS-55 Digital Scale (or equivalent), these are commonly used rules of thumb for calculating draw pull (courtesy of CTT):

Scale	Cars per Ounce
"O" gauge	3
"S" gauge	5.2
"G" or "L"	1.2

Wire Current Carrying Capacity

As printed in the National Electric Code 310-17, to follow are the maximum current carrying capacities for THHN type wire. Note temperature rating of the insulation (this chart is 90 degree C insulation rating) and assumes free air application (no conduit) (from OGR thread):

AWG (Gauge)	Amperage Rating
18	18
16	24
14	35
12	40
10	55

Related input from Lisa Marie Tahtaras: "When wire heats up, its resistance increases. While this has little affect on a 120V circuit, it makes a lot of difference on a 12V circuit." The recommendation here is use a heavier gauge wire and quality connectors.

Distance/Amperage Chart

AWG wire sizes vs. usable output in amps. Distance is maximum length of wire in one side of the circuit (from Trains.com).

Distance	1A	3A	5A	10A
8 feet	22	20	18	16
12 feet	20	18	16	14
20 feet	18	16	14	12
30 feet	16	14	12	10

Trackwork and Wire Capacitances

Trackwork	Configuration Measured	Capacitance
Atlas 2 rail track	rail to rail	5 pF/ft
Atlas 3 rail track	center to running rails	11 pF/ft
GarGraves Track	center to running rails	25 pF/ft
Lionel 40" track	center to running rails	50 pF/ft
Ballast for above tracks, add (est.)		15 pF/ft
16AWG lamp cord, 2 cond in plastic		20 pF/ft
12AWG THHN 600V on 2" centers		3 pF/ft
12AWG THHN 600V on 1/2 centers		5 pF/ft
14AWG wire, cable-tied in harness (est.)		10 pF/ft
12AWG line-wire, center of dbl-trk main		15 pF/ft
35 ft test yard, line-wire average		7 pF/ft
35 ft test yard, 22AWG 8" overhead wire		2 pF/ft

* From TCA's Train Collector's Quarterly, July 2003

Resistance Values

Component	Resistance
Lionel® LW Transformer	0.63 ohms
MTH® Z4000 Transformer	0.43 ohms
Lionel® PowerHouse 180	0.29 ohms
MTH® TIU Controller	0.20 ohms
Lionel® TPC3000 Controller	0.10 ohms
Hammond 165S18, 10A	0.08 ohms
Hammond 165U18, 15A	0.05 ohms
Hammond 165V18, 20A	0.04 ohms

Conductor	Resistance
16AWG wire	4.0 mohms/ft
14AWG wire	2.5 mohms/ft
12AWG wire	1.6 mohms/ft
GarGraves rail	7 mohms/ft
Atlas Ni-Silver, code 200	5 mohms/ft
Brass rail, code 172	2.8 mohms/ft
Brass rail, code 210	1.8 mohms/ft
	(mohms = milliohms)