A Look Back In Time: Remembering The D78 Stock

 The day is April 21st 2025. We’ve spent a lot of it furnishing our new shed, using upcycled bits from tube stock lost to time. I  realised that 8 years ago on this same day these trains had left service after 37 years of exceptionally reliable service.

These trains are also heavily ingrained into our DNA at Rail Tags from a personal point & an excellent story of industry upcycling.

With their unique shape, single leaf doors and sounding identical to their Piccadilly Line cousins, With their iconic shape and striking a balance between a retro and modern look this is the D Stock and they deserve to be remembered.

Prepare for a bumper packed blogpost.

1. Pre History & Entry Into Service:

During the early 1970s we saw the arrival of the much loved C Stock onto the Circle & Hammersmith and City Line (Batch One: C69 Stock). The arrival of these new C69 Stock trains saw the pre war built CO/CP Stock trains cascaded onto the District Line from the Circle and H&C. This allowed the withdrawal of even older 1923 built Q Stock trains and the CO/CP Stock joined operating alongside the R Stock on the District. This was always meant to be an interim solution, maintaining the two different generations of fleet made maintenance a challenge. In response to this The London Transport Executive GLC drew up designs for a uniform fleet of trains which became to be known as the D78 Stock (D Standing for District and 78 standing for the year they aimed to enter service)

In 1976 The London Transport Executive GLC placed an order with Metro-Cammell for 77 six car trains but was later amended to 75 trains at a cost of £67.8 million. The design of the D78 Stock was thanks to German industrial designer Jurgan Greubel with Sir Misha Black taking helm of interior colour scheme.

Production started two years later in 1978 at Metro-Cammell’s Washwood Heath factory. The trains were built to feature LT118 traction motors built by BRUSH and pneumatically driven camshafts built by GEC Traction in similarity to the pre existing 1973 Stock on the Piccadilly Line. The D78s were also built with large single leaf doors with door operation buttons in contrast to previous units featuring double leaf doors, transverse & longitudinal seating was also included, the D78s also had head and tail lights positioned under the driving cabs which was a change from having the headlight built into the front facing body of previous tube stock. Another commonality these trains shared with the Piccadilly Line 1973 Stock was the bogies, being the same but slightly modified.

D78 Stock trains would operate in a six car formation as previously opposed to seven cars with the CO/CP and R Stock with the trains being built with carriages measuring at 18 meters each.

Many innovations were made with the production of the D78s such as Metalastik Chevron primary springs and Diabolo shaped secondary springs allowing for a smoother ride for passengers which gave the D78s their signature “croaking” sound at low speeds. The drivers cab were ergonomically designed with a drivers seat that could swivel forward and back, up and down. The deadmans handle was replaced by a joystick style combined traction and braking controller, the D78s were also the first to be built with a Train Management System replacing the previously designed Train Equipment Panel which would simply highlight faults to the driver. The trains were also built with a “POGO” switch standing for Passenger Open / Guard Open that switched the role of releasing the doors from the passenger door buttons to direct control of the guard, they would operate the doors from the rear cab.

The first D78 Stock entered service on the District Line on the 28th of January 1980, a common problem with the newly introduced trains was overheating caused by the windows which caused them to be modified.

 

2. Operational Legacy On The Underground:

The final D78 Stock was delivered and put into service during 1983 and they would operationally cover the entire District Line apart from the Edgware Road branch which starts at High Street Kensington, this was due to the trains being too long to be accommodated in the platforms and with a lack of SDO this saw more C Stock trains ordered around the same time as their production, the second batch being known as the C77 Stock.

During the mid 1980s, several three car D78 units were sent to operate on the East London Line to cover for A Stock units that went for One Person Operation conversion. (Modern day we know this method of operation as DOO) the A Stock trains returned to the ELL in 1987.

Thames News: D78 Stock on the ELL Video

On the 18th of September 1987 unit 7100 crashed into the buffers at Richmond Station and overran into the concourse glass in West London causing minor injuries to sixteen people.

Despite the crash at Richmond and another two or so derailments during their career, the D78s had a relatively quiet working life but this isn’t stated in any negative way. The trains were hailed for their excellent reliability amongst District Line Train Operators, further discussed below.

Reliability: 

The D78 Stock is often hailed as the most reliable fleet that London Underground has ever operated, sometimes reaching 35,000km but on average 19,000km between failures. This can be attributed to the design of the units which had a lot of it’s components tested previously on the 1973 Stock but modified for use with the D78s, we will get to the commonality between the stocks later in the blogpost.

3/1. Refurbishment:

Most London Underground Stock had their refurbishments during the 1990s as a part of a modernisation programme however the D78 Stock was not shortlisted in this programme due to their relatively new age compared to other rolling stock, being around a decade old by the time the programme was started. However in the late 1990s they were close to turning 20 years old in the new millennium which saw refurbishment plans finally take effect.

In 1999 unit 7008 was selected for a trial refurbishment of the fleet and was done at Acton Works funded by Metronet Rail and lasted until 2003.

In July 2003 it was announced refurbishment would take place at Bombardier’s Ilford works, however due to the scale of the project this was not the case. In August 2003 the first D78 Stock left the District Line via Acton Depot for a design finalisation programme at Wakefield Works.

Through the rest of 2003 two more units moved to Wakefield for the refurbishment programme with later units being moved to Derby Litchurch Lane.

The refurbishment contained: the new London Underground Corporate Livery being applied with anti vandal paint, a completely restyled interior featuring car end windows and PIS scrolling displays, rubber flooring replaced the maple wood flooring, the addition of opening and closing hustle alarms, covering up the door open buttons, grab bars replaced hanging straps, CCTV, a disabled multi purpose area, air condition added to the driving cabs and a new audible passenger information system voiced by Emma Clarke.

Unit 7002 was the first to return in October 2004 for extensive testing which first started at the South Ealing Test Track on the Piccadilly Line, a lot of rumours floated about regarding their entry to service and understandably a lot of excitement was fostered over the units.

Eventually in June 2005 the first unit entered passenger service with the other D78 Units following until 2008, the D78 Stock would continue to plough their trade into the 2010s. But something inevitable marked from the refurbishment programme was creeping closer and had already claimed their spot on the Metropolitan Line from the A Stock…

3/2. Enter The S7:

Back in 2003 the Metronet consortium became responsible for managing the sub surface lines on the Underground as part of the London Underground Public Private Partnership. In the consortium was a plan to standardise the fleet across the four lines with 190 trains to be built by Bombardier with designs being revealed in 2006. However in 2007 Metronet had collapsed due to financial difficulties leaving London Underground / TfL to take on the responsibility of delivering the programme.

In 2009 the S8 variant entered service on the Metropolitan Line, with the much beloved A Stock being withdrawn by 2012 with one unit being kept for Rail Adhesion duties and a carriage preserved at Acton Depot, the rest were scrapped at CF Booth in Rotherham. Next on the chopping block was the C Stock which was replaced by the S7 variant. The first C Stock left our rails in 2012 and the final one going in 2014.

Whilst the S Stock’s have proved their place on the London Underground being all around great units, seeing these trains replace the C Stock left a bitter taste in my mouth. They were my number one favourite train at the time, I remember getting World of Subways Volume 3 and driving them for countless hours as well as on OpenBVE which had a really impressive model. Driving them on simulators and games at the time led my curiosity to ride them in person and I ended up really appreciating their sleek New York-esque style.

After the grim scrapper had claimed the A and C Stock trains, the D Stocks were next and last on the chopping block. (Well, kind of)

In 2014 Vivarail, a relatively new rolling stock manufacturer had signed a deal to purchase 156 driving motor and 70 trailer cars off London Underground for conversion into units fit to run on the UK mainlines. This was done with the intention of filling in a gap in the market for affordable new rolling stock.

Withdrawals of the D78 Stock commenced in January 2015 with the first units 7510 and 7058 being hauled by road to Long Marston for conversion works to the mainline classification of “Class 230”. One of my only favourite memories of secondary school funnily enough involves these road moves. I remember starting Year 7 back in 2015 and being on break a couple of times, my school field overlooked a dual carriage way and sometimes I would see D78 Stock trains get hauled past on their way to Long Marston. I was not expecting to see that at the time so you can probably expect I had a very “surprised” reaction to tell you the truth.

Unfortunately though, it signified another important era of my childhood was coming to an end being the D78 Stock (More on that later). The majority of carriages would end up being sent to Long Marston for conversion with only a handful going to scrap.

Another memory I have from seeing them be withdrawn comes from a school trip to Acton Depot in February 2017 towards the end of the rollout period.

It was lunch time and most of us on the trip was sat in a room having lunch whilst the Depot Logistics Supervisor invited me to come tour the depot which was arguably way better then having lunch… I got to see an A Stock and C Stock up close for the first time in years, as well as check out the D78s short lived twin the 1983 Stock.

I got to head outside the main shed where I was stood behind D78 Driving Motor 7508 which was probably be stripped for spare parts (I don’t remember the reason why) but it was the first time I was at foot level staring up at these massive carriages and realising I won’t get to look at them the same I had done since I was a kid.

 

4. #CatchTheD:

Only two months later on April 21st 2017 units 7007 + 7032 operated the last day of service for the D78s, marking the end of a bespoke and nostalgia era of the District Line to amazing fanfare.

London Underground helped to promote the occasion and #CatchTheD trended online with the units schedule posted for people to track. Hundreds of enthusiasts turned up to catch one final trip with multiple services throughout the day being fairly packed with both commuters and enthusiasts alike.

7007 and 7032 adorned special vinyls on the front ends.

The first service of the day was the 0624 service from Upminster to Richmond, with the last ever being the 1635 service from Upminster to Ealing Broadway. Many turned up for the final service and to see the train off to Ealing Common Depot from Ealing Broadway station.

At the time of withdrawal the D78 Stock was 37 years old which was considered “young” by normal withdrawal standards with many considering they could have had a longer life.

Two weeks later on May 7th, a farewell rail tour was hosted for the D78 Stock which would cover the entire District Line (except the Edgware Road branch), Northfields branch of the Piccadilly Line and West Ham Sidings.

This was the first rail tour I ever went on and made sure I went, not managing to get a ride on a D78 since late 2016. It was one last chance to say goodbye, and a proper chance to say farewell. Everyone on board got a special brochure filled with the history of the D78 including details of the Vivarail D-Train project.

Here are a few photos captured on the day:

The only D78 Stocks left on the London Underground Network is the DM from 7012 which resides at the London Transport Museum’s Acton Depot, and units 7010-8123-17010-8010-7123 / 7040-8107-17040-8040-7107 as Rail Adhesion Trains based at Neasden Depot.

5. Upcycling:

The D78 Stock story did not end with the Farewell Railtour in 2017. Since then there has been multiple uses for some trains.

Back in 2016 Driving Motor 7027 was donated to Coopers Lane Primary School to act as a library which is quite the remarkable story, similar to C77 Stock Driving Motor 5720 which now resides at Plumcroft Primary School.

7027 was taken out of service and transferred to Acton Works. Trailer 17027 and UNDM 8027 were scrapped whilst Driving Motor 7027 was cleaned, repainted and had it’s traction motors and other underbody gear removed before being transported by road through London to Coopers Lane where it was craned into the playground where a mock station was built around the carriage.

The carriage still resides at the school today and excellent care has been taken of the carriage to keep it looking as sparkling as when the D78s came back from refurbishment. According to Luke Agbaimoni aka Tube Mapper the carriage is now used as a play area hopefully inspiring the younger generations to take up a career in rail one day.

 

5/1 Vivarail: 

Coming back to the topic of Vivarail, after purchasing a great portion of the D78 Stock fleet from London Underground the carriages were all transferred to Long Marston for conversion into mainline capable units.

They thrived off innovation, and at the time they had ambition towards a massive achievement but how did they fare?

Vivarail was the brainchild of the late Adrian Shooter, a man well respected within the rail industry who had a strong passion for it too. He carries a strong everlasting legacy revolutionising wherever he went. Shooter joined the railways in 1970 as a management trainee before going to multiple different roles.

He launched Vivarail in 2012 with the intention of filling a large gap in the rail industry market for new and cheap rolling stock, the premise was to take the basic bodyshell of the D78 and outfit them with brand new equipment and bring them up to modern standards indicating the large amount of life the D78s still had left. Through Vivarail the D78s were upcycled into Class 230 and Class 484 units.

The 230s being capable of Diesel Electrical, Diesel Battery or sole Battery operation which was thoroughly tested and proved to work.

Unfortunately multiple hitches along the way meant the programme struggled to gain traction with London Northwestern Railway, Transport for Wales and South Western Railway’s Island Line being the only sole operators of the units.

The LNWR units were the first to enter service in 2018 and operated on the Marston Vale Line until 2022 when Vivarail went to administration withdrawing the fleet without a designated maintainer, the TfW units came about 5 years later then scheduled due to multiple faults during testing and the CoVID-19 pandemic whilst the Island Line Class 484s would have the smoothest introduction and still operate to this day with one unit being out of service due to water damage.

In late 2022 Vivarail went into administration after failing to achieve funding after the American Railroad Development Corporation, their main shareholder at the time pulled the plug.

Sadly, not long after Adrian Shooter passed away at the age of 74 after battling motor neuron disease.

Regardless of what you think of Vivarail as a company and how well they have done, you always have to appreciate the attempts people make to better the industry. GWR have picked up the rights to the Vivarail fast charge system and Class 230 001 is currently testing on the Greenford – West Ealing Branch, my fingers are tightly crossed it’ll enter passenger service…. oh to ride a D78 again.

 

6. Personal Thoughts On The D78 & The 73 Stock Connection:

Phew… I’ve finally got through all the facts and details regarding the life of the D78 Stock, to round things off I want to take a more autobiographic approach on the influence these trains have had including their close relationship to the 1973 Stock which I openly express my fondness on.

As previously stated in the blogpost, the D78 Stock has taken a lot of it’s technical inspiration from the 1973 Stock including their motors and how they’re propelled. Despite the clear contrast in design choice the familiarities are very easy to identify if you have ridden on both these trains.

They sound identical throughout from the air brake pressure release to the wind up and down of the traction motors.

The D78 Stock was the second type of train I remember coming into contact with during my infancy. Living on the Heathrow branch of the Piccadilly Line for a good 1-3 years they were the only railway territory I had explored until one day we ventured East towards London (by this time, I was already very into trains). Like cavemen discovering fire or Newton discovering gravity I realised other types of trains existed outside of the Piccadilly Line and the D78s were the first glimpse I had into the world wide railways.

The image is still in my mind and the thoughts when I first saw one. Me and my grandad were on a 73 Stock speeding up towards Hammersmith on the Eastbound and as we passed Chiswick Park I looked out the window and saw a train way taller then ours with a completely new shape. This was around the time the refurbishment programme was ongoing and it was striking seeing one in a shiny new LU corporate livery matching the 73 Stock we were on.

Completely unlike the 73 Stock trains I had been so used to, it was mind-blowing knowing there was so much more to explore. This was a time before the internet so going out to London blind not knowing what to expect it was all about seeing what trains each line had. To my grandad it was “take the young lad out and show him the world”, to me it was “what does the trains on the pink line look like if the green line has these type of trains?”

As I grew older I felt more indifferent to the D78 Stock due to being so used to seeing them on frequent trips out, apart from having fun racing one out on the Eastbound at Acton Town. When the S Stocks came in and replaced the C Stock, I realised how much borrowed time the D78s were running on which is when I started to truly appreciate their trade. Their unique and simple design would soon fade forever out of my life further signifying how the railways change with the time.

For Christmas 2016 I was surprised with a pair of seats taken from a unit which is where I really started to collect railway memorabilia, that was when I started to discover the hidden art of railway upcycling.

Those seats sat in our garage for 9 years, until three days ago (21/04/25) when the perfect opportunity came to use them being our new workspace which is still currently being furnished. I’m happy I’ve managed to give a pair of seats continued life for personal use, retired from the career of being sat on by too many commuters over MANY years… when the time came to pull them out the shed and prepare them for a new lease of life in our studio I ended up on YouTube watching videos of D78 Stocks, it feels like a lifetime has gone by since they left the District Line and that is where the memories pooled in from.

Closing Remarks:

Despite the obvious nostalgia trip I have just gone down, the D78 Stock has cemented it’s legacy on the District Line as underappreciated workhorses for their continued reliable service which became sadly outmoded a little bit too soon by more modern S Stock trains which are proving to stand the test of time themselves now. Their story is fortunately not over, with some Class 230 and 484 unit seeing continued revenue service on the national rail network, further honouring the late Adrian Shooter who’s idea it was to save some of these great trains from the scrapyard and being forgot to time. Thankfully you can still see a D78 on the Underground Network for one season each year when the Rail Adhesion Train wakes up from it’s hibernation and helps keeps the track clean from leaves. Who knows what the future holds for those two RAT units, but for now it’s great to still see some kicking about on their truest home, the London Underground.

Long Live the D78 Stock.

(psssst! there are still tons of carriages scattered around the UK all in varying condition, two in Barry Island a few in Long Marston Unimetals… we know what needs to happen but can we pull it off?!)