This comment brought back some vague memories. In fact there is some footage on Youtube of loading trials at Castle Bromwich. The video linked below is a slideshow of pictures showing Land Rovers and Range Rovers being loaded to open flat wagons back in 2017. If you look on the same channel there are a few more short videos, including footage showing the loading of Jaguars to both decks of the WIAs, and careful checking of clearances as they load different models of Land Rover / Range Rover over the ramp onto the flat wagons. Interestingly, the mobile ramps allow loading over the top of the buffer stops.
Video: Photo Compilation - Loading Unloading Trial
Channel: Mark Moore
After that trial, the Castle Bromwich service did start using some STVA wagons around 2018 - searching "6O30 Southampton" on flickr brings up various photos. From then on about half the train was WIAs with the rest being STVA flat wagons (loaded in two adjacent sidings as per the video).
Original formation entirely made up of WIAs (2015):
https://www.flickr.com/photos/186579225@N03/50188954692/
Using (mostly) open STVA flat wagons + WIAs (2018):
https://www.flickr.com/photos/16645820@N06/43251383742/
Using covered STVA wagons (TDT852) + WIAs (2020):
https://www.flickr.com/photos/robmcrorie/49497925031/
This photo from 2018 clearly shows the Range Rovers (Velars?) and Land Rover Discoverys loaded to the train:
https://www.flickr.com/photos/terry47401/46356909391/
These would have been produced at Solihull and would no doubt be too big to fit in the double-deck WIAs, which are not designed for SUVs. The Jaguars produced at Castle Bromwich itself remained in the WIAs by the looks of it. I'm not sure what the likelihood is of this traffic restarting, but if it did it would be a good candidate for using WIAs again.
The WIAs were also originally used on the Halewood to Southampton flow. In Paul Shannon's recent book
Rail Freight: North West England, there's a photo of a train of WIAs leaving Halewood, with the caption stating this traffic commenced in 2001 for Jaguar. On flickr, there are photos of WIAs on this service up until around 2010 - the daylight return working around this time ran as 6M58 from Southampton to Warrington:
https://www.flickr.com/photos/113923498@N03/12618182434/
In 2011 there was a big investment at Halewood and it started producing the Range Rover Evoque. This expanded the number of trains (up to 3 departures a day as 6O38 / 6O42 / 6O46) and also required a change of wagon type (to the covered single-deck TDT852s) due to the size of the vehicles. In the Freightmaster Publishing book "Loco Review 2012" (some of those Loco Review books are very cheap second-hand on Ebay, lots of nice photos) there's a 2011 picture of some brand new TDT852 covered STVA wagons being hauled from Dollands Moor to Didcot by a Colas 66, probably for that flow.
There's a Youtube video of the WIAs arriving at Micheldever as a 4Z21 on 21/8/09, which ran from Wembley. The 3 WIAs had reached Wembley from Dollands Moor, having spent some time on the other side of the channel (I have no idea where they went or what they were doing; possibly being trialled for use on mainland European flows).
Video: 4Z21 66077 with WIA car carriers at Micheldever oil terminal sidings 21/8/09
Channel: justinfoulger
I think the choice of Micheldever as a storage location was probably just somewhere to keep a few of these these enormous wagons out of the way without taking up siding space in busy yards or paying rent for storage (I assume DB must own those sidings). For many years there would have been space in the former Washwood Heath yard for spare automotive wagons. With all the changes to siding and yard ownership, siding space is at a premium these days in many locations.
Eastleigh TMD started maintaining the Virgin Voyager fleet years ago and I think the depot may have shifted more into passenger train maintenance / storage / commissioning or whatever they do there these days (they still service some DB locos working into Southampton Docks). GBRF took over the operation of Eastleigh yard, meaning it's not quite so simple to drop off wagons from passing DB services and trip them into the TMD. The depot appears to operate under the "Arriva TrainCare" brand these days -
https://www.arrivatc.com/eastleigh/
Stock photo with a good view of the repair shed:
https://www.alamy.com/stock-photo-a...iving-maintenance-at-eastleigh-172456577.html
STVA wagons sometimes receive maintenance at nearby Eastleigh works, occasional wagons being attached to Halewood - Southampton car trains and tripped across. On one occasion last year there were evidently enough wagons to justify a special move from Eastleigh Works to Dagenham, with DRS 57002 providing power -
https://www.flickr.com/photos/ianmartian/50274874183/
STVA wagons also visit Telford for attention on the "as required" trip from Warrington Arpley. There's a weekly tripper between Warrington, Garston and Halewood which connects these wagon maintenance moves together and also provides a link into the Dagenham - Mossend services at Warrington. There's some nice footage of the Telford working here, with a VSOE-liveried 67!
Video: Class 67024 working 6G51 arriving at Donnington Rail Freight Terminal
Channel: Jacob's Rail Adventures
Nice to see that video. Looks like the side screens on the upper decks have been temporarily removed - I don't think you could fit an actual roof without being significantly out of gauge (certain car models on the upper deck can already slightly exceed the standard loading gauge, requiring X headcodes and special paperwork, as 3973EXL mentions).
I think the situation with migrants in the Channel Tunnel has improved a lot since the days when they caused major disruption to freight trains. The big camp at Calais was closed, and £5 million spent on improvements to security fencing according to wikipedia -
https://en.wikipedia.org/wiki/Calais_Jungle
https://en.wikipedia.org/wiki/Channel_Tunnel#Illegal_immigration
Trains are now moving between secure yards on each side of the tunnel, with checks involved at both ends, making goods trains a more challenging prospect compared to hiding in the back of a lorry, or sailing across the channel on a boat. It doesn't mean the tunnel is 100% secure, just that there are easier options...
Vehicle security (from damage or vandalism) will come down to a trade-off between costs and risks of different wagon options; those kind of decisions will be very familiar to a company like STVA - according to the CAT Groupe website they shipped 8.9 million new vehicles in 2018, 7% by rail, so they should know what they are doing! Having said that, vandalism can certainly be a potential problem - there's a paragraph in Paul Shannon's excellent book
Rail Freight Since 1968: Cars, Containers and Special Traffic which mentions a flow of Vauxhall Astra estates from Ellesmere Port to Purfleet in early 2000, which ceased running due to unsustainable levels of vandalism. It's a shame this traffic didn't (or perhaps couldn't for some reason) switch to using the WIAs...
I think the best chances of the WIAs being put back into use (and the reasons for retaining them) would be:
1) For a high-value or vandalism-prone flow which needs fully enclosed wagons (such as the Jaguars from Castle Bromwich if that flow resumed)
2) For an increase in volumes / extra services on their existing Cowley workings
3) For some new flow where STVA has no involvement, where the customer needs the haulier to provide wagons
I was pleasantly surprised by the Toyota announcement, so who knows what developments could occur in the future...