Specifications

Width (Left-to-Right): 6.1" including track centerline ridges
Depth (Front-to-Back) 2.7"
Height:1.2" including feet
Weight: 0.4 lbs. with batteries installed
Case: Polycarbonate, transparent amber, UV stabilized for outdoor operation.

Caution: This instrument contains lead (Pb) solder. Lead is a dangerous material known to cause health problems. Do not open the enclosure other than to install batteries.

Operating Temperature Range: 32 to 100 degrees F.
Batteries: Two AAA, alkaline preferred.
Battery Life: Operating: >120 hours. Standby: shelf life of battery.

Display

Liquid Crystal, wide viewing angle, digits are 0.7" high for easy viewing.
Right Display: Grade in percent.
Left Display: Superelevation in inches of superelevation.

Grade Readings

The grade measured is the % grade measured along the track centerline. This is Rise over Run so a 1" rise in 100" run displays as 1.0. There are track-center ridges on the ends of the instrument to assist in getting accurate grade readings. For sharp curves in the smaller scales, see operating notes.

The grade reading is 0.0 to 9.9% accurate to +/- 0.2. The instrument also displays steep grades of 10 to 40% accurate to +/- 1.0, and 41 to 99% accurate to +/- 3.0

Superelevation Readings

The superelevation measured is the height of one rail over the other. 6.0 inches of superelevation displays as 6.0. The measurement is taken along the sides of the instrument. Align one edge along a tie or otherwise perpendicular to the centerline. On straight track or on gentle curves, this alignment occurs naturally if the track-center ridges on the ends of the instrument are aligned with the track centerline. For sharp curves in the smaller scales, see operating notes.

The superelevation reading is 0.0 to 9.9" accurate to +/- 0.2. The instrument also displays superelevations of 10 to 20" accurate to +/- 1.0, and 21 to the gauge width accurate to +/- 2.0

Scales

The instrument is independent of scale. It works on N-Scale through G-Gauge through Live Steam through Prototype 1:1 scale.

Although it was originally designed for garden railroads, for smaller scales, where the instrument cannot fit because of trackside structures, etc., or larger scales, where the instrument is too small to lie on the rails, see operating notes.

Gauges

Grade reads directly in percent regardless of gauge.

Superelevation reads in scale inches of superelevation on standard gauge (4'8.5") track, but this can be changed to any of these supported gauges: 2-foot, 30", 3-foot, meter, 42", standard (56.5"), 5-foot. Also, the gauge may be set to none for modellers who wish to see percent rise over run on both axes.

operating notes GM-20 Main Page