一行车 sounds not strange "行"(hang 2nd) is often used to describe something lined in a row it seems that we use "排" more often, "排" has similar meaning to "行" so in many cases , you can replace "行" with "排" e.g. 一行文字(a line of text) 排成两行(to line up in tow rows) 排成两排(to line up in tow rows) 排成两列(to line up in tow columns) but you cant say 行成两行 because 行(hang 2nd) is not a verb ,in contrast ,"排" can be a verb or a noun

We usually use 辆 to describe a car 一辆车. Maybe he means lots of cars in a line, so he wrote 这行车 or 这排车