The average size of road motor cars had risen since the 1960s when the Cartic-4s were built. There were also issues with the 200ft length of the Cartic-4 sets. This precluded small loads, required lengthy sidings and was inefficient in that a failure on one wagon would result in the whole set being taken out of service. The Procor 80 aimed to address these issues as well as improving on the Cartic-4 design in other respects. The headroom on the lower deck was increased, while the angle of the slopes at each end was shallower, reducing the risk of cars grounding. The side pillars were staggered so that loading drivers could more easily access cars and, although the wagon had to be made narrower due to its length, the inner faces of all side pillars had rubber bumpers. Up to 10 cars could be carried, generally with 6 on the lower deck and 4 on top, but this number would be reduced when carrying larger or estate cars. The height of the end loading decks was the same as on the Cartic-4, thus allowing mixed trains and the use of existing loading ramps.

The first batch of 11 Procor 80s was built between 1979 and 1981 and was given numbers PR90872-90882 with TOPS code PLA and design code PL001A. PR90872 was painted in a red livery with the decks and all inner faces being white. It was used as a demonstrator and had lettering for Procor and was prominently branded as the 'PROCAR 80 Car Transporter Unit'. The name is of interest in that all subsequent references to the type (including by Procor themselves) gave the type name as Procor 80. One of the new wagons, most likely PR90872, took part in the Rainhill 150 cavalcade in 1980, being marshalled into a short train made of modern wagons. The red livery was still carried but the lower 'solebars' had been repainted blue. PR90872 later (by 1987) gained Toleman blue livery and worked with the second batch of wagons. The remaining ten wagons from the first batch (PR90873-PR90882) were hired to Renault to carry imported cars from Goole Docks and carried a yellow livery with large Renault lettering and diamond logos.

The second batch comprised 25 wagons numbered PR908883-90907 and was built between 1981 and 1982. These went on hire to the Toleman Group and were painted in their bright blue livery. Uses were initially carrying imported cars from Harwich to Bathgate and in 1986 all 25 were sold to Tolemans and reprefixed TOLD.

Wagons from both batches were modified within a few years to try to protect their cargoes from the unwanted attentions of vandals. However, the length of the Procor 80 meant that fixed screens, as used on Cartic-4 sets, were not an option. Instead, specially shaped canvas or PVC sheets were fitted to cover most of the lower deck openings and the sides of the upper deck. No top-side protection was possible. The Toleman wagons had blue sheets with translucent panels on the lower deck. The Renault wagons are thought to have had yellow sheets, but they certainly included large Renault lettering and the diamond logo.

Interestingly for such modern wagons, the Renault batch was taken out of service and stored at Goole by 1989. PR90882 was repainted white with matching side sheets and was used to try to attract new users. It had large lettering for new owners Caib and appeared at various exhibitions and trade shows but does not appear to have been successful. In 1990 the PLAs were recoded JLA with design codes JL001A and JL001B. By 1995 the Tolemans wagons were also withdrawn, being placed in storage mostly at Tonbridge. There are a number of factors which may have influenced the early demise of this type. These included the lack of top protection (which was by then being provided on many of the Cartic-4 wagons) and the slight route availability restrictions caused by the Procor 80's length. However perhaps the most important was the increased competitiveness of road haulage. New lorry designs capable of carrying more cars appeared in the 1980s, and road transport also had the obvious advantage of not requiring any special infratructure such as loading ramps.

With no new car traffic in prospect, a plan was hatched to convert some of the JLAs into plant carriers for use by the Civil Engineers. At the time, items such as bulldozers were being moved using elderly Flatrols. The conversion work would have involved the removal of the sides and upper deck, plus the strengthening of the lower deck. The plan was eventually shelved in favour of a new build of air-braked well wagons (KWA) but it is possible that the bogies from the JLAs were used on these or other new-build wagons. All the JLAs were removed from TOPS (and presumably scrapped) by the end of 2005.