Cov AB wagons VAA and VBA - what's the difference?

[Hippel]

Hi, can anybody tell me what the difference between a VAA and a VBA is, please? I've looked on Paul Bartletts site but can't see any physical differences between them except for experimental suspension on some vehicles.

 

Thanks

Paul.

[Mol_PMB]

I thought this would be an easy question to answer but I was wrong!

 

http://www.barrowmoremrg.co.uk/BRBDocuments/Book320Part1Issue.pdf

lists the following diagrams:

 

I think the 'VAB' coding applied to many vans was an error during the transition from 'COV AB' to the TOPS codes, and this certainly confuses matters.

 

This document actually includes the vans, though I think it's a slightly later issue and doesn't list all the same variants. I'm sure you can do some more digging among the diagram books on the BarrowmoreMRG website:

http://www.barrowmoremrg.co.uk/BRBDocuments/Book320part4Issue.pdf

 

At a quick glance, there were many different types of suspension used, and these accounted for the different diagrams.

There was also one batch with ventilators in the ends.

 

[Davexoc]

I think the difference was the suspension, the VAA was built with UIC double link, the VBA being the result of the experiments, and having FATxx depending on build. The bodies are very similar, which then changed with the later VCA and VDA derivitives.

[Mark Saunders]

As far as I can tell it’s the UIC double link and Long Link that’s the difference!

[Hippel]

Thanks, guys.

 

Paul.

[BernardTPM]

The last A would be air-brake, B air brake with through vacuum pipe, so VAB could be correct. At the start of the 1970s these air-braked vans could be included in a vacuum braked train if fitted with a through pipe.

Edited August 9, 2021 by BernardTPM

[Rivercider]

5 hours ago, BernardTPM said:

The last A would be air-brake, B air brake with through vacuum pipe, so VAB could be correct. At the start of the 1970s these air-braked vans could be included in a vaccum braked train if fitted with a through pipe.

I also understood that the code VAB that was applied to a number of vans was an error, with all the VAAs being air braked only, none having vacuum pipes.

As well as the VBAs there were a number of vacuum piped VBBs. These VBBs were useful as they could be marshalled in fully fitted vacuum braked services, or in the vacuum braked portion of a partly fitted train. One type of traffic that VBBs were used on was bagged china clay out of various locations in Cornwall, they could be marshalled with the OWVs and UCVs of clay with no brake van required.

 

cheers

[HGR]

This was certainly one of those cases where 'learning as you went along' was evident in the introduction of TOPS.

 

The original intent when the GENKOC (the first two letters) part of the TOPS code was allocated around 1973 was :

VA = COV AB (full length doors, and included both ventilated and non-ventilated variants)

VB = COV CD (centre doors)

[ at this time, VC was assigned to CATTLE vans ]

 

As mentioned by earlier posters, the third letter (BRAKTY) was 'A' for air braked, and 'B' for vehicles air braked & vacuum piped.

 

The fourth letter in the 'full' TOPS vehicle type code - AARKND was originally supposed to be 'N' for non-ventilated, and 'M' for ventilated.

 

The Design Codes (the diagram numbers e.g. the pages in the vehicle diagram books as per Barrowmore MRG web-site) were first assigned in 1975, by which time :

 

VA = VAN, full length doors - (ventilated or non-ventilated)

but was quickly changed to

VA = VAN, full length doors - (ventilated)

VB = VAN, full length doors - (non-ventilated)

VC = VAN, centre doors

 

As the process of assigning Design Codes to vehicles had already commenced when the change of ventilated / non-ventilated definition occurred, the upshot was :

 

VA 001A which was the only genuinely ventilated variant (the 200100 - 200119 batch) remained where it was. This was VAB.

VA 001B to VA 001H which were the non-ventilated variants, were all re-coded in the range VB 003A to VB 003G, but unhelpfully not in the same order. These were VBB except the last two types which were VBA. 

VA 002A which was a ventilated COV AB with experimental suspension was re-coded VA 001B in the place now vacated by the above non-ventilated re-codings. This was done to fit in with how Design Codes are grouped according to differences in vehicle characteristics. This one was a VAB.

 

Many of the VAB later lost their through vac pipes, becoming VAA.

 

The only other odd one out / 'prototype' was B 787395 which was initially given VV 022A in the general ventilated vans but later re-coded VA 010A. This also was a VAB.

 

The centre-door COV CD initially given VB 001A to VB 001C and VB 002A were rapidly re-coded VC 010A to VC 010D (again in different sequence), two types were VCB, other two VCA. Note that this group had to start from number 010 because there were already cattle vans occupying VC 001 - VC 007 (all of which vac braked VCV).

 

As above, the incoming re-coded non-ventilated vans then dropped in to VB 003 onwards in the now otherwise emptied VB group. Some were correctly re-branded VBB or VBA but not all were done correctly. Just for good measure, some of the ventilated ones that should have remained VAB / VAA got accidentally re-branded VBB / VBA as well. 

 

Just to add to this, of the vans originally lettered COV AB a not insignificant number had this modified to the TOPS code simply by painting out the first two letters to leave 'V AB' as the supposed TOPS code, often regardless of whether they did still have the vac pipes or not. This is partly the reason why many non-ventilated vans were running around as 'VAB' when they should have been VBB or VBA. TOPS users in the AFCs tend to only input the vehicle number into TOPS so a discrepancy between the train list output by TOPS and the code painted on the side of the vehicle would not have been that much of a concern at the time. Always worth carefully comparing vehicle number range and painted TOPS code in photographs.

 

The snippets of the vehicle diagram index in one of the posts up-thread are from the original, first issue of the index. If you look in later copies of the diagram book there will be an index with the later pages marked 'ISSUE 2' that will show the Design Codes as resulting after the change to the VA / VB definition. Beware that the index pages were released individually, so a revision to issue 2 would apply to just that page. There were also some interim revisions that were not released as new ISSUE numbers, usually to expedite typographical corrections but sometimes to sneakily insert new vehicle types or delete ones that had become extinct.

 

 

 

 

 

 

 

[hmrspaul]

They would all have had a vacuum pipe when new - pretty useless without that as there were few all airbraked general merchandise services. 

 

Mark appears correct in the type of suspension being the intended difference between VA and VB, but if you look at my photos BR workshops didn't follow this intention through as efficiently as modellers might like to believe. Nothing neat about BR, probably those originally being written COV AB added to the confusion, as did the numerous experimental suspensions on many of these vans. 

 

Paul

[Flood]

HGR has covered the full details but as he states in 1975 the VAA (VAB) was solely for the ventilated variety, VBA (VBB) for the non-ventilated. In reality the first batch 200000-200208, were virtually, if not all, coded VAA (VAB). The remaining batches were VBA (VBB) although some errors can be seen on individual wagons being coded VAA (e.g 200633, 200643, 200644).

Edited August 9, 2021 by Flood

[Rivercider]

Every day is a school day!

I first started in Bristol TOPS in October 1978, I never remember dealing with any VABs, which of course does not mean there were none by then, whereas I do remember VBBs being relatively common,

 

cheers. 

[hmrspaul]

17 hours ago, Rivercider said:

Every day is a school day!

I first started in Bristol TOPS in October 1978, I never remember dealing with any VABs, which of course does not mean there were none by then, whereas I do remember VBBs being relatively common,

 

cheers. 

Couple of VABs in 1981 https://PaulBartlett.zenfolio.com/brvaa/e29ed8e93 in 1984 https://PaulBartlett.zenfolio.com/brvaa/e112f9229 I've not looked further. 

 

Paul

[HGR]

On 09/08/2021 at 15:09, Flood said:

HGR has covered the full details but as he states in 1975 the VAA (VAB) was solely for the ventilated variety, VBA (VBB) for the non-ventilated. In reality the first batch 200000-200208, were virtually, if not all, coded VAA (VAB). The remaining batches were VBA (VBB) although some errors can be seen on individual wagons being coded VAA (e.g 200633, 200643, 200644).

Just been having a further dig regards the 200000 - 200099 / 200120 - 200208 batch. As you point out most were coded VAA or VAB and it got me wondering how come so many of these were showing up as this even in Railfreight and EWS liveries after all the later batches had been recoded. If you discount the ones that became assorted barriers or runners or transferred to the departmental fleet, the many left of that batch were showing up on TOPS as either Design Code VA 001A (VAB) or later as VA 001C (VAA), both of which it lists as 'ventilated'. Only the intermediate batch of twenty had ventilators on the ends (originally dia. B.R.1/267 in the old books), the rest (dia. 1/248) which were the majority of the batch had a note added 'ventilated doors, except 200033 to VBA'. Now I can't for the life of me ever remember any of them having doors that were intentionally ventilated any more than the deteriorating door edge seals ? Can't see any means of ventilation visible on the doors despite a scroll through Paul Bartlett's excellent web-site.