“In the factories Toyota created a role called ‘team leader’ made up of hourly production workers selected for their leadership potential. The group leader seeks out team members with potential, and encourages them to go to team leader training, and then mentors them over time until they have the skills needed to lead a team of 4 to 7 people. They pay the team leader a little bit more per hour and they guarantee them over time so they can come to work early and make sure everything is set up right. Production starts at the “go” sign, and then proceeds smoothly right from the first minute. They are also the first responders to andon calls from one of their team members. I am getting behind, I am getting ahead, or I see that I might run out of parts. For whatever reason, if I am out of standard, I pull cord, a light goes on, and music plays and somebody has to come to help, and the team leader is generally the first to come. This of course means the team leader cannot be working production or they will not be able to respond to the andon.” 
Developing Lean Leaders at all Levels by Jeffrey K. Liker with George Trachilis (Lean Leadership Institute, 2014) p. 178.

“Team Leaders take on a number of responsibilities traditionally done by ‘white-collar’ managers, though the are not formally managers and do not have formal authority. Their prime role is to keep the line running smoothly to produce quality parts (immediate response to andon) and to resolve problems when there are deviations from standard.” 
The Toyota Way 2nd Edition by Jeffrey K. Liker (McGraw Hill, 2021) p. 207.