Robert G. "Tunnel Bob" Gruenenwald
At 6' 6" and with a distinguishable gait to his walk "Tunnel Bob" is hard to miss if you see him above ground. Wearing a Green Bay Packers stocking cap 365 days a year Bob has had a lifelong affection for the steam tunnels running under the UW Madison campus. It seems he would rather spend his time down there than be around people. He would also replace light bulbs in the tunnels, or report problems such as flooding or steam leaks to campus authorities. He has had numerous minor run-ins with campus police, many the result startling people by popping his head up out of a tunnel entrance. Bob still patrols the tunnels though most are off-limits because of the dangers of asbestos, heat, high pressure and high voltage. Access to the tunnels has also become more difficult since the September 11, 2001, terrorist attacks.

The Tunnels are a century-old system of tunnels supplies steam to heat most campus buildings, snaking along for several miles beneath campus buildings, roads and open spaces. Built in 1898, two sets of steam tunnels encase the pipes that now carry steam from the main heating station on Charter Street to most buildings on campus. A second facility at Walnut Street supplements the Charter plant. Despite its age it is not considered old-fashioned, instead, it's economical when compared to the cost of running a separate heating systems.

In all, there are about 10 miles of tunnels. Some are four-foot-high box-conduit tunnels; some are six-foot-high walkable tunnels. The tunnels also contain electrical, compressed air and technology lines.