LYNN – At the Great Woods entrance of the Lynn Woods Reservation, every Wednesday evening since the end of May, runners gather in the parking lot in the shadow of Joe Abelon’s 23-year-old white GMC truck.Abelon conducts the registration for the Lynn Woods Summer Cross Country Races out of the back of that truck, from which he dispenses race numbers and helps compute the results of each evening’s races (the usual number seems to be three).The races at Lynn Woods have been going on for 41 years, and they have shown both popularity and longevity. Abelon’s fellow race guru, Bill Mullen (who has been involved with the races for “31 or 32 years”), said that the races drew over 200 people each night for most evenings this summer.The races are free of charge; Abelon and Mullen donate their time to help run them.”We have drinks and cookies,” Mullen said, “and except for one race, the relay, you come, we give you a number, we time it, and if you’re willing, you put a buck or two into the can.”On Wednesday, Abelon summoned runners to the starting line on the concrete at about 6 p.m. The choices were a short race (2.2 miles) on the Goat Path, a longer one (4.8 miles), and a kids race. Runners had to specify which race they would run beforehand.The 2.2-mile race introduced its participants to the hills of Lynn Woods almost from the get-go, with one runner wryly noting that the opening hill got to her every time. Some people ran in groups, chatting as they navigated the stony footpaths. Some shouted encouragement to fellow runners and helped each other navigate the trails.Lynn Woods isn’t Mile High Stadium, but the trails do elevate, allowing runners to see the reservoir. On the summer race website, www.lwrun.org, prospective participants can view different course maps, including their altitudes. For instance, there is a 2.5-mile course with a starting altitude of 118 feet and a highest point of 220 feet.”It’s an acquired taste,” Mullen said. “We had 500-600 unique people this year who acquired the taste.”Near the end of the 2.2-mile race Wednesday, orange traffic cones had been placed in rows on the grass beside the parking lot, with runners darting through them to the finish line by Abelon’s truck. Abelon was busy inside at his computer, charting and printing the results, which he posted to the side of the truck.”It used to be a very local set of people,” Mullen said. “Now it’s a much wider set of folks, from Burlington, Billerica, Cambridge, who somehow found out about us and repeat every week.”The races began when Abelon was coaching at St. Mary’s, got a job at Tech, and wanted to do “something in the summer,” he said. “I thought I would have a race up there, on the right side of the reservoir, up and back.”The winner of the first race was Bob Sevene, who would go on to coach Joan Benoit (later Joan Benoit Samuelson) to a gold medal at the Los Angeles Olympic Games in the summer of 1984.Wednesday’s races were the penultimate edition this year. The grand finale will be this coming Wednesday.”The woods are a wonderful place to run,” Mullen said.