I’d like to see more MUs, 313/317 type sets, I don’t hold out hope though as the 320/321 has been a bit of a slow project, maybe the MU especially EMU trains just don’t appeal to most modelers.
Well, Ben and Mike have just gone and announced the class 313 so I thought I would pick the other half of this post and propose a class 317 EMU along with my reasoning.
Class 317/1The class 317/1s were built in 1980 for the newly electrified Bedford - St Pancras line and the Widened Lines branch to Moorgate. They were the first production units to be built using the new steel Mk3 surburban bodyshell. They were rather boxy in appearance with unique letterbox window ventilators and were unkindly described at the time as having been designed by a colour-blind spot-welder with a grudge. When new, they were delivered in blue/grey livery. They quickly spread to become one of the most widely travelled EMU units in the south-east.

The 317/1s were quickly displaced from the Bed-Pan line by the arrival of the class 319 units and Thameslink. In spite of this, the class returned to their original home many times to work supplemental services to Moorgate, right up until the current decade. Initially, the class was split between the WCML out of Euston and the ECML out of King's Cross where they worked outer suburban services alongside the inner suburban 313s. With increasing deliveries of 321s on the WCML, they migrated to the ECML and West Anglian routes out of Liverpool Street and were repainted in NSE livery.
317334 at South Kenton in 1988 with the Watford DC lines in the foreground.

317344 at Bethnal Green with a service to Liverpool Street in 2003, still wearing NSE livery nearly 10 years after privatisation.

317315 on a service to York on the ECML. This unusual working was the result of a derailment at Sandy. Normally the class worked the services to Peterborough, Cambridge and Kings Lynn.

Following privatisation, the class went on to wear a truly spectacular array of liveries as they continued working on various London suburban routes. They added the London, Tilbury and Southend route of Fenchurch street to their CV meaning they have worked on every 25KV route into the capital apart from the GWML. Not only that but they have worked alongside classes 313, 319 and 321, all of which are coming soon RTR which means that anyone modelling a 25KV line in the south east can probably fit one of these units in.
317307 in LTS Rail livery on a down train at Barking.

WAGN Class 317 No. 317340 at Welwyn Garden City

In 2000, nine Class 317/1 units were selected to be refurbished for the dedicated Stansted Express service and received new window frames and a revised front end design. The nine units were reclassified as Class 317/7 and would require a different tooling. But the remainder of the class received a much lighter refresh and still basically resemble their original condition although now being spread across assorted subclasses. Here is a gallery of some of the liveries the class has worn over the years, I am sure their are others.
317506 at Liverpool Street in National Express livery

317348 at Peterborough in FCC livery

317891 in London Overground livery at Enfield Town

317345 in "black stripe" livery at Cambridge

317348 at Cambridge North in Great Northern livery
