The Baydron-class (also known as the J4-class) was a type of starship used by the Romulan Star Empire's Star Navy in the 23rd century. The J4-class was a class V transport design that entered service active on reference stardate 1/96.
The Baydron vessels crewed 32 Romulans, with room for 40 passengers and one shuttlecraft, as well as two transporter rooms, one 6-person personnel transporter stage and a single cargo transporter. The J4s measure 200 meters in length, 150 meters in height and 35 meters in height, with a weight of 55,600 metric tons. The vessels have a cargo storage capacity of 60 SCU, or 3,000 metric tons, as well as engines rated to haul 160,000 metric tons of cargo containers outboard. Control computers on board were of the R4M type. The J4 had two RWC-2 warp nacelles, with an unloaded cruising speed of warp six and a maximum speed of warp 8, although fully loaded reduced each speed by two warp factors. The impulse engines were of the RIB-3 type. The ships were defended by KSN type deflectors
The D2 series entered service around stardate 1/96, with over two-hundred fifty ships constructed for the Romulan government, with over 180 of those remaining in service by the 2280s, and a matching number sold for use in private industry. New vessels are constructed at a rate of 30 per year, with two-thirds that number going to use by the state. The ships were named for Senator Baydron of Messala. (FASA RPG module: Romulan Ship Recognition Manual)
Presumably, the first ship of this series would have been called Baydron, although such a vessel was never specifically named in the sources mentioning this class.