311103 at SummerleeFreshly painted in BR Blue livery with yellow ends, 311103 is seen on display at Summerlee 18.8.03 In 1967, the Inverclyde lines (Glasgow Central - Gourock and Wemyss Bay) were electrified and there was a need for a further batch of Electric Multiple Units to operate the lines.   19 Class 311 (then called AM11) EMU's were built. 

Unfortunately, Pressed Steel, who had built the Class 303's just a few years earlier had closed down by this time, therefore Cravens of Sheffield were chosen to build the Class 311s.

311103 at SummerleeA forlorn looking 311103 at Summerlee 22.12.12 The class 311s were almost identical to the class 303s, they had the forward view from the passenger saloons of the driving trailers, passenger operated doors and had seating for 236 people, however there were also a few differences.  

Firstly the 311's were built to only run at 25Kv AC, where as the Class 303's were built as dual voltage sets, to allow them to operate at 6.25Kv AC in areas of limited OHLE clearance and at 25Kv AC.   

There was additional vents on the side of the Class 311s motor coach next to the Guard's Compartment to allow more airflow to reach and help cool the transformer.   Internally, the decor was more modern than that of the class 303 and each unit was fitted with fluorescent lighting from the start, rather than the Tungsten Lighting fitted to the class 303.

When built, the 311's were painted into the all over BR Blue livery with yellow warning panels on the cab fronts but soon recieved BR Blue/Grey livery.   The numbering scheme followed on from the final 303 to be built (303091) and they were numbered 311092 - 311110.  

311103 at SummerleeA view of the Guards Van end of 311103's motor coach is seen on display at Summerlee 18.8.03 The 311's started life on the Inverclyde lines, however after developments in the Overhead Line technology, that allowed the 6.25KV sections of wiring to be upgraded to 25KV and the use of dual voltage areas to be abolished, the 311's found their way onto other lines including the Cathcart Circle, Hamilton Circle, Lanark services and North Clyde lines as the 303's and 311's could work in multiple with each other.

There were plans to upgrade the class 311 for the electrification of the lines to Ayrshire, however it was found to be cheaper in the long run to get newer stock built (class 318s) therefore the 311s remained in unrefurbished condition for their working lives, with 50 of the class 303s chosen for refurbishment instead.  One modification that was carried out though was the replacement of the curved windscreens replaced with flat toughened windscreens.   

Three of the fleet would also be repainted into the Strathclyde Transport 'Red' livery, however the majority remained in BR Blue /Grey livery for the remainder of their working lives.   

311100 became the first class 311 to be withdrawn, with a further three sets being withdrawn in 1987 and a 5th in 1988.  A further 4 sets were withdrawn in 1989, leaving 9 remaining in service heading into 1990.

311103 at SummerleeA forlorn looking 311103 at Summerlee 22.12.12 In 1990, a fleet of 22 BREL built class 320s were being introduced into service on the North Clyde lines to replace the remaining unrefurbished class 303s and the entire class 311 fleet.  Most of the class 311s were scrapped with the exception of two sets, 311103 and 311104, these were to live on in the Glasgow area with a new use as Sandite units, spraying the track with a solution to aid the grip for trains in the leaf fall season.   311103 would be renumbered 936103 and 311104 as 936104.  They remained in use until 2001, when with the impending withdrawal of the class 303 fleet, they were replaced by Multi Purpose Vehicles (MPVs).     

311104 was scrapped at Immingham in 2002 whilst 311103 was destined for preservation at Summerlee Heritage Park in Coatbridge, where it was repainted into a coat of BR Blue.   However in 2006 when the park was being refurbished, the set was moved from its prominent position in front of the main building to an area round at the back at the furthest point away from the entrance.   Driving trailer 76414 was sold to VSOE who wanted the bogies for underneath one of their Pullman carriages, whilst the remainder of the vehicle was scrapped.   The 2 remaining vehicles had their windows covered with corrugated cladding to protect their windows from vandalism.    

311103 at Summerlee311103's ongoing repaint into Caledonian Blue livery at Summerlee as seen during the Classic Car show 27.4.25 In June 2022, work began on a tidy up and repaint of the remaining vehicles of 311103, with the driving trailer and the motor coach receiving Caledonian Blue livery with off white roof that was originally carried by the class 303s on introduction to service.   Whilst Caledonian Blue isn't prototypical for the class 311 as it's original livery was BR Blue, it is a nice livery and one that isn't currently represented elsewhere in preservation.   

Whilst the repaint is still a work in progress, 311103 is still looking so much better than it did previously!