BIKEPGH MESSAGE BOARD ARCHIVE

That may have been a nuclear density gauge. Google "Troxler" if the following image doesn't show up properly: It is a device used to measure the density of soil or other materials being used as a based for pavement as a way of checking if it has been compacted enough. The probe (which looks like a hand pump) is inserted into the soil. The base of the device has some sort of radiation meter built into it. Depending on the amount of radiation that is able to pass through, the density can be determined. They are regulated by the nuclear regulatory commission. I've used them some years ago before but never had to deal with geiger counters or flag off an area with cones. However, if they were testing along the trail while it was open to the public, I could see the potential need for some extra precautions.

Brent, The equipment was very old looking (the geiger counter was an old analog needle readout type), and was separate from the pump/hose. However the process you mention could very well be what they were doing with different equipment. Thanks for the info, makes me feel a little better about riding through.