David Wilmes was among the thousands of Metro riders caught up in the Friday evening crunch at Fort Totten station after a train derailed outside West Hyattsville and shut service on part of the Green Line.

He had to wait 42 minutes at Fort Totten for a Greenbelt-bound shuttle bus. At that hour, not long after the derailment, the scene at Fort Totten was chaotic, he observed. There were lots of police, but apparently few Metro employees to direct riders. The police were friendly, he said, but had no information. Lines were long, the sun was hot and directions were scarce.

But this wasn’t the worst encounter Wilmes had with the Green Line last week.

On Tuesday evening, he was among the riders aboard a train stranded in the heat outside the College Park station. Wilmes provided a calm and detailed account of his experiences that was published as a letter in my Sunday column.

I hope transit staffers and Metro Board members will read his description and conduct a thorough review of this dangerous incident.

“Maybe it’s time to take up driving to work again,” Wilmes wrote to me after the Friday disruption. I think he was kidding, but if not, who could blame him?

The Friday derailment was serious business and also deserves a thorough review, but the Tuesday event was at least as disturbing. Friday’s emergency response went pretty well, according to the reports we’ve received.

Tuesday’s response was very different, and unnerving. Riders were wandering around on the tracks, with little or no supervision after receiving little or no information about the status of rescue efforts.

Here’s an excerpt from the letter that Wilmes wrote:

After efforts to restart the train failed, the operator “walked back through the train and came on the loudspeaker to tell us that another train would come through from Prince George’s Plaza to push us into the station. All of that took [an estimated] 30 minutes. After that, we heard nothing.

“For 25 to 30 minutes, we sat there without any information. A woman on my car was on the phone with Metro and was told that the train behind us [the rescue train] had also lost power.

“We could see the operator walking by the train and fiddling with an electrical box. We also saw a handful of people leave the first car and head to the station, which prompted conversation about whether the train was being evacuated. About five minutes later, the operator got on the loudspeaker to say: ‘The third rail is down. There is no power going through it. I guess you can all get off now if you like.’ ”

Do you know how to evacuate a Metro train? Here’s what happened aboard the car that Wilmes was in:

“On my car, passengers read the printed instructions on how to open the door and filed out one by one. It appeared that the same was happening in the other cars. To get down from the car, we had to jump down about three feet. Some people struggled with this, but others helped them.”

They walked along the tracks into the College Park station, a distance Wilmes estimated at 600 yards. You can see a photo of them doing this on the unsuckdcmetro blog.

Good grief. It’s not just the nearness of the third rail. The riders are trudging along through gravel within striking distance of any train or track equipment that might come along. Metro workers have been injured or killed this way.

Just what happened when during the evacuation remains unclear. Did some passengers aboard that hot train, lacking information, begin the exodus on their own?

“Maybe there was more going on in the other cars, and certainly a few people did leave the train before the operator gave her go-ahead,” Wilmes said in his letter.

It will be interesting to sort that out upon further review, but these are the basics: A Metro train broke down during a heat wave. The cars got hot. There was very little information. Riders were unsure what action was being taken to help them and when that help would arrive.

As time passed in silence and the train got hotter, what would you have been thinking? I’d have a laser-like focus on a single concept: Get me out of here!

The transit authority is correct to say it’s dangerous to be wandering on the tracks unsupervised. In fact, it’s extremely dangerous. It’s the transit authority’s responsibility to make sure that doesn’t happen.

But it did happen. That’s the bottom line, and the reason this incident is so disturbing and so in need of investigation.