That was the job I enjoyed the most. The reason is really simple, I didn't punch a time card and had no direct supervision. Another contributing factor I never knew what I'd be called upon to repair. By field that means out and away from any kind of building, could be in the mountains, crossing a farmers field or even public lands. Two of my more memorable. A Caterpiller D-7 dozer operator was 4 miles back cutting a road into the side of a mountain. A lot of large rock to push when somhow he spun and snapped both track locking pins causing both tracks to come apart. The road was still not passible by truck so hauling the tools and parts needed to make the repair took ingenuity. I had a John Deere 450 dozer and blasting mat brought in. Loaded tools, large acetylene & oxygen tanks, dry ice and dragged those to the work site. Took all day but was able to tell the foreman he could have his operator continue the next day. Another was deep in a forest with a winding road. Hauling poles back to the construction site the steerable trailer used stopped steering. The 12 volt motor inside the hydraulic fluid tank that provided the hydraulic power to steer quit. With cement delivery and more poles scheduled that trailer had to be repaired that day. No problem just open the tank remove the motor and buy a replacement. OOOPS the motor was special, only replacement was in Germany. The cost of delay would be huge. No option but to take the motor apart to try to find out why it quit. Once the outer casing was off I could see the winding had snapped off the connection. Whew not to bad, just unwind one layer,solder the connection, melt a votive candle to wax over the windings, test & reinstall. Then there were other no pressure repairs like rebuilding a rear under the vehicle. A mild challenge. The pinion snapped because the operator was sunk a few inches in frozen mud and tried to move it. A little tricky getting it out and back in but that is what made the job interesting.