From left to right: Ryan from NWPR, Eric, Marco, Jensen
On July 9th and July 10th, we conducted a series of technical tests on Northwestern Pacific Railway tracks next to Sonoma.
Our main objective during those tests was to ensure the structural stability of the train. Our secondary objective was to capture data to ensure the accuracy of our top speed estimation.
The I-beams used as the backbone for the structure are very flexible and we added multiple X-braces to reinforce the frame. However we were not sure if this was enough or if we would have dangerous oscillations that might cause the train to derail. To test safely, we built a remote control system, so the train can be driven at high speed with no-one onboard.
Using a 30’ trailer, we moved the train from the workshop to Shellville Train station, set it up on the rails there and drove south to the test location.
Ryan, from NWPR, was the railway expert guiding our team during the test and was driving a Hi-Rail truck to accompany.
The solar train number is STX22: ST for Solar Train, X for a car not owned by a railway company, 22 for 22% solar panel efficiency.
The first day
Just after the road crossing, the train derailed at the first curve: the spacing of the wheels was not correct (too narrow). Fortunately, we were travelling less than “ludicrous speed” and we were able to change the spacing quickly on-site to re-rail the train.
We drove through the rail yard up to the first test location: about 2 miles of straight tracks. We then tested the stability of the structure and verified that the remote control system is working as expected, using an onboard phone to provide the network connectivity.
“Kill switches” on each end of the test section were placed on the track to trigger the brake automatically in case we lost control of the train when nobody was onboard.
We ran out of time to conduct more tests: the sun was already low in the sky and we had to use our battery pack to go through the shadow of the rail cars parked in the rail yard.
The end of the first day: solar train vs oil tankers.
The second day
That day, we received the authorization to drive outside the rail yard. We decided to drive down to Petaluma River, past Sonoma Raceway, since there is a 4-mile straight section there of welded rails. This is about 10 miles away.
Driving south, we kept the speed at 10 mph to ensure that the drivers were safe. So it took about one hour to reach our test location, taking one bridge and crossing one major road (highway 37).
After setting up the test section, we ran many technical tests and collected data. We ran the train up to 25 mph (remote controlled) without issue. The sun decided to call it a day before we were ready so we were not able to reach a higher speed on that section of the track.
When we drove back, it was already past 6pm. We barely made it through the shadows of trees and hills. When we reached the rail yard, our pack battery was completely discharged so we had to use some muscle to power the train the last mile.
End of the second day: the sun is low in the sky
The technical tests were successful:
Next step: Add the body panels and test at a higher speed!