The Bridger class photon artillery is a type of support unit used by the Federation.
These vehicles are capable of firing powerful photon shells into enemy positions making it a deadly opponent on the planetary battle theatre. These shells are similar to Photon torpedoes but lacked a guidance system. This reduces the shells attempt at tracking moving enemy targets. However, against fixed based structures, it excels at its job. In order to commence firing sequence, the craft had to come at a standstill for it to orient its weapon system.
However, the slow speed these vehicles were capable of made them easy targets for fast moving enemy vehicles. Thankfully, battle tactics allowed these artillery pieces to attack from a rear guard role as they did not require line of sight to attack enemy positions.
A type two advanced model was also produced which added additional elements in the chassis. This allowed the vehicle to field more weaponry and thus shoot more photon shells into enemy locations. The additional room allowed for a better delivery system as well as more powerful shells to be stored effectively. Despite all these improvements, the Bridger Model A is just as slow as its predecessor which is why Starfleet has ordered that all Bridgers are escorted into the battlefield by Brigadoon class phaser tanks.