HGR

Was the mass exodus of 12 T VANFITs in the early '70s around about the same time parcels traffic was disappearing off the railways ? A cull at this stage would have fortuitously saved someone a sizeable job entering all of them onto TOPS. I remember the rail blue SPVs that had been repurposed from FISH vans also going around this same period - including the body of E 87009 randomly appearing in the middle of a field at Sadberge near Darlington. The 1N21 / 1D21 Doncaster Works Test Train that used to run round at Tyne Yard or Darlington, etc. depending on its progress managed to gain a string of these SPVs as a load for some years - later being replaced by a rake of plain blue LMS full brakes, then more latterly by blue/grey Mk.1s.

Are you meaning MC 011B in the earlier scanned images ? If so, it's the stiffening bars that some of the pre-nationalisation types had. Ones of L.M.S. origin in this instance. Although not amongst the above scans, the various diagram MC 001 variants are the B.R. 1/108 MINs. Design codes / diagrams MC 001A to D are the re-bodied ones (diag. B.R. 1/99) with various types of brakegear. MC 001E to J cover the non-rebodied B.R. 1/108 again with various forms of brakegear - unfitted, vac, with and without empty/loaded changeover. Partial replating was simply counted as repair, so would not be evident in the diagrams. Bear in mind that the first allocation of TOPS codes for wagons was made in 1970 / 1971, but the actual 'go-live' was not started until 1973 and took a couple of years to spread throughout the system, by which time some of the more obscure stuff had gone by the wayside so didn't last long enough for those vehicles to actually have received the allocated codes. So some of these diagrams might have never seen any vehicles in service. There were certainly plenty of diagrams missing from and struck through in the index of the first issue B.R. (B) TOPS diagram book. In general, within any group of design codes, at initial allocation of the codes the air-braked designs come first, then the rest of the B.R. designed diagrams, then the pre-nationalisation types. After that, new additions are appended to the list as and when they crop up.

Thanks ever so much for all the scanning you've been doing. In theory the diagrams that I hadn't requested are the ones that survived to revision 4 so I have copies of in my post-'83 books albeit possibly at later issue than the originals you have in your copy, or they are air braked and tucked away in the last part of the weirdly re-organised early book 320 that I have, but you've got me on VW 002A ... it should have been on my list but I missed it, if you have it please ? Revision Letter 1 is what got you from the B.R. (B) series books into the first issue of Book 320. Please can you have a look at the Revision Letter 1 for Part 4, to see if it lists any diagrams that were amended or added ? (part 1 had some diagram amendments, but parts 2 & 3 were just the covers changed from the look of it). Can you have a look to see if any of your book 320 parts have a copy of Revision Letter 2 and 3 ? If your pile of loose diagram pages does throw up missing ones that you don't have in Book 320, but are on my list, then you could well be sitting on the goldmine that is the stuff culled during or prior to the B.R. (B) books. Particularly also if you find diagrams that are not in book 320 and neither are on my list. For example if you come across HM [001A] that would have been allocated to the bogie iron ore hoppers used on the Tyne Dock - Consett ore trains. These survived up till 1974, but I never saw any with TOPS codes on them. Mind you, didn't see any with '64 style 'boxed' lettering either for that matter ! Just 56 T above the wagon number.

Yep, till the mid-'80s the TOPS code VVV just about covered all sorts of anything with doors and a roof that reflected many different by then past traffics which had by then coalesced into what could be described as no better than sundries. Then all of a sudden there was a vast clearout and all the interesting stuff evaporated ... mostly into farmers' fields, other than what picked up departmental prefixes, or internal user numbers. Fruit and Ale to finish, that's two of your five-a-day ... what a result ! One thing about cattle vans : The dia. 354 ones were drawn the other way round to all the others so the internal partition was at the left end instead of to the right. I've not been able to find enough detailed underframe photo's to see if the brake gear was the opposite way to the body on these compared to other cattle diagrams ? Thanks.

It's a MS Excel file, but noticed that the file attach on these posts includes them, so should be OK. Might do a 'print' of it as well as PDF in case there are people who don't have (or dislike) MS Excel. What it does do is highlight some of the anomalies in the diagrams - see for example VV 009C ... AARKND is VVVV (not VVVC as you might expect given the type of vac brake fitted). This may well be a typo, as there was no VVV-V on the RSL vehicle type lists as far as I'm aware ? I'm trying to get it up to the codes around in the '90s, which is about where my involvement in these sorts of things got to. Once it's pretty much done I'll post it.

Thank you once more for your continued work with these. It's much appreciated and filling in a fair chunk of missing knowledge in my technical 'library'. For whatever reason, the British Railways (B) books, and copies of various early revisions of Book320 that I have are devoid of the part(s) where the vans lurk. The copies posted by various people on Barrowmore MRG seem to have a similar trait - almost like the old vans were very secretive ! Think I mentioned before, my two parts of B.R. Diagram Book (B) only gets you as far as the end of the 'O' OPENs group. Anything after that I'm missing. Back in those days, there weren't revisions as we have now. Instead, the D.O. issued 'Circular Letters' numbered sequentially one upwards as each revision was issued. Each C.L. contained a raft of various amendments to be made by hand to the diagram pages in the books. Mine include Circular Letter No. 3. Dated 14 June 1977. I'm not aware that there were any more C.L.s after that until they went to Book 320. Fortunately whoever updated the (B) books that I have did not remove / destroy the pages for diagrams that were 'cancelled' - they are still in there for historical interest. In 1981 there was a big project started in the D.M.& E.E. which produced the 'REVISED VEHICLE DIAGRAM BOOK NUMBERING SYSTEM' so that the various TOPS diagram books all now lived in one big series. Locos used to be in the MT specification section, as were cranes / tracklayers. Wagons were pulled from the B.R. (B) and P.O. (P) books. Coaches, which hadn't been tackled so far under TOPS, had to be done afresh, notwithstanding that despite NPCCS being the first coaching stock to go onto TOPS, was the last book to make it out of the D.O. ... not appearing until 1986 ! Now revisions came out under cover of a 'Revision Letter', again numbered in sequence from 1 upwards in order of appearance. So, to move the freight stock (B) books into Book 320 in the new series, Revision Letter No.1 dated February 1982 provided the new covers and a selection of updated and new diagrams to incorporate. Seem to remember Revision 4 was the outcome of the big 1983 - 85 re-coding (and vehicle renumbering) exercise in order to allow all of the coaching stock to be accommodated by TOPS without the poor computer getting confused by owner / prefix or number 'vehicle origin' suffix letters. In the case of wagons, it cleared out the 'J', 'K', 'X' groups etc. for re-use elsewhere. Revision 9, out in 1990 was the last Revision I received, which lasted till the 'end-of-days' (or privatisation as the Government called it). After that, Railfreight Distribution (RfD) continued the tradition. One of the sets of Book 320 parts that I managed to acquire had weirdly been rearranged to have Vac Brake and Unfitted (in Part 1 and Part 2 covers), getting as far as 'OU' codes, and Air Brake and Air Pipe No 2 (in Part 4 cover), starting with 'OA'. Probably better suited the way they worked for preparing consists. So I'm guessing the missing Part 3 cover would have been Air Brake and Air Pipe No 1, and held the rest of the vac / unfitted - including the runner wagons, 2-axle (or more accurately, rigid) steel carriers, uncovered and vans, and then the bogie steel AB, Freightliners, MGR / domestic coal hoppers, minerals and so on. So yet again, none of the older vans that I'm interested in ! This particular set of Book 320 parts seems to be a revision 1 plus two distinct but very late sets of updates inserted. How bizarre ? To try to make some sense of the various revisions of diagrams, I'm putting together an index so I know which book to look in, or on Barrowmore, or these posted by SED Freightman. On the subject of issue numbers on diagram book pages, beware that these don't directly relate to the TOPS design code that they appear on. Instead they relate to the underlying engineering drawing that forms the diagram book page. So for example the drawing for COIL K which started out as TOPS design code JK 001A was revised to ISSUE 1 with the design code amended to BN 001A when the remaining vehicles in the 'J' group were re-coded into 'B' group etc. So if you're looking for the predecessor of an issue revision, never assume it was the same design code. SED Freightman : I know you're probably not going to want me to say this, but your pile of removed diagram pages may well be worth a scour for the ones that got blitzed during (B) book period / pre or early Book 320. There are lots of diagrams struck out in the first issue of the (B) book index, but I'm not sure if these reflect types that were around in 1970 when the TOPS codes were first allocated, but didn't last long enough (till 1973) to actually make it on to TOPS, or ones cancelled due to becoming extinct after that. Anyway, a big thank you for your perseverance with the scanning.

Thanks SED Freightman. I'm guessing many of the ones you're missing in the initial issue of Book 320 could well be those that went in the '70s. Where no lot numbers are listed in the index against the diagram it often is for pre-nationalisation types, which could of course be early candidates for withdrawal. For VS 004A/B and VS 005A however these are later B.R. lots than the other SHOCVANs so not sure what would have happened to them ?

Different numbering series keefer ... the cl.40 locos for use at Crewe were given cl.97/4 numbers 97405 - 97408, and the Peaks dropped into the 97/4 series later. The battery locos were cl. 97/7.

Close but not quite ... different vehicles of the same batch of conversions. (though typo I guess ?, next key along the keyboard, prefix was LDB) Originally short-frame (57') motor coaches DMBSO from disbanded North London Line cl. 501 units. Passenger saloons gutted and filled with battery racks. Windows plated over with ventillation grilles. Flat section to roof for access to OLE. End doors added for use in tunnels. They were coupled back-to-back in pairs. Ten vehicles done over the period 1973 (DB 975178/9 later LDB..., then became 97701/2 for Merseyside), 1975 (LDB 975407-10, later ADB..., then became 97707-10 for GN electrification based at Hornsey). The batch for the Bed-Pan electrification ordered in 1978 as LDB 975673-6 were cancelled first time around, and came out later in 1980 as 97703-6 without carrying the originally allocated LDB975... numbers.

Thanks again SED Freightman. Going back into the very dim and distant now. I wonder if the banana van diagram being missing meant that they had all been lost into the general van pool or re-used as barrier wagons by then ? Can remember seeing some of the later corrugated end sort coded RBV. Some still had the BANANA lettering. ISTR some carrying code VVV.

S 61872 was the one-off motor coach on lot 30641 that was put in 4 EPB unit 5302. Does anyone have a photograph of the roof of this unit with enough detail to tell if this vehicle had only one periscope, as it would for a dia. 414 vehicle, or did it have two periscopes ? Alternative may be an interior shot of the guard's van to see if it had the extra periscope in the middle of the van for when the driving cab was leading, as well as the one on the bulkhead used if the coach is at the very rear of the train. Some sources attribute dia. 400 to this motor coach, which implies two periscopes. If a roof shot after the periscope(s) removed, there would be rectangular blanking plates covering the slots in the roof where the periscopes previously were. The significance is that the instruction originally was that the guard should ride in the rear-most van in the train. Southern region four-car units up to '57 stock had a motor coach with a van at each end, adjacent to the driver's cab. Consequently a four-car unit bringing up the rear of any train formation would have the rearmost van such that the guard would only need one periscope to look towards the middle of the unit, and hence forwards in the direction of travel. A two-car unit only has one van, in the motor coach. It could be facing either way round at the rear of a unit formation, so necessitated two periscopes so the guard had a forward-facing view regardless of whether the unit was running motor coach leading or trailing. 5302 being a four-car EPB would have only needed a single periscope in the van, so this motor coach could well be to dia. 414. However, it later migrated to other units such as 2 HAP 6151, meaning that either it had two periscopes (or was modified to be so), hence dia. 400, or the use of periscopes had been discontinued by that time.

Likewise, done a bit of digging also. You've found an interesting one there. It appears DB 999506, and DB 999508 - 9 were originally ordered from Swindon to GWR dia. Q 13 and should have appeared somewhere around the late 1950s, but by the time they were built they became rather Mk.1 style, with only two end windows (the placement of which means they didn't have the standard end framing / crash pillars). The diagram 1/552 lists them all as being built 1963 ?

Beware that you might have come unstuck with these. B.R. perpetuated a couple of types of these ... one sort based on LMS diagram 2046, the others to GWR diag. Q 13, so neither count as Mk.1. There was ISTR one of the original LMS saloons that had its body transplanted on to a Mk.1 underframe, complete with B4 bogies. Can't remember if it was the General Manager's saloon or the one that used to go around with the royal train pre-1977.

The designation of 'Mk' appears to have come about when the second variant of 'integral design' coaches came out as Mk. IIA. Up till then, what was later termed Mk. I were generally referred to as 'Standard' stock. The first 'integral design' coaches then picked up the identifier Mk. II. British Railways set up the Standard Carriages committee (SC). There were likewise committees for Standard Locomotives (SL), and Standard Wagons (SW) though the latter is a far more loose concept to get your head around. The drawing office output of each of these is reflected in the format of the drawing numbers : so for standard coaches, SC, followed by a '/' then two letter code identifying the works / drawing office, another '/' and followed by an index number usually from 1 upwards. And yes, the code for Swindon was, you guessed it, SW, so wagon drawings from there go SW/SW/1 onwards. Within the SC drawings there were two lengths of underframe - commonly referred to as 57' (short frame) and 64' (long frame). The actual lengths over headstocks were 56'11" and 63'5" respectively. These seemingly obscure dimensions, when applied with standard buffing / drawgear components yielded body lengths that were round numbers. The frames could be used with fixed screw couplings, British Standard suspension gangways (even offset for TPOs) or Pullman type. The end of the body was flat if non-gangwayed, or with 6" angled side panels if gangwayed. So, short frame stock came as 57'6" or 58'0", and long frame stock came as 63'6" if flat both ends (non-gangwayed), 64'0" for vehicles such as EMUs with flat inner end and angled driving cab front, and 64'6" for vehicles gangwayed both ends or at least fitted with Pullman rubbing plates. Some builders / works found ways to introduce some small variation in body length - possibly not helped because some quoted length over body framing instead of overall length. Notwithstanding the roof was a standard length, but it would take more than the casual observer to spot the difference between the 'standard' two and a half inch overhang, and ones with only two inch or one and a half inch. On some vehicles the overhang was different at the two ends ! (surprisingly common within EMUs) The 'standard' design of underframe as used on hauled stock and DEMU / EMUs, was a 200 Ton strength. Many DMMUs used the standard underfame (and hence body) lengths, but on a much lighter weight underframe with correspondingly lower strength. Hence you weren't allowed to put 'lightweight' DMUs into goods train consists with a heavy load behind them. They later painted 'LW' on the ends above the buffers to warn shunters of this less-than-obvious feature. As to body profile, this was a fixed radius curve in standard stock, with the widest part at the height of the middle door hinges. There were flat sided varieties as well, for vans. Also various reduced widths for stock on lines with limited clearances. Many DMMUs did not use the standard coach body construction components, hence the variation in body profiles between particularly the contractor supplied stock. I would agree that these lightweight DMMU don't really count as true Mk.1. There are some DMMU that are Mk.1 construction proper, even if they have B.S. suspension gangways. They tended to come from places such as Swindon, such as Inter Cities Diesel Trains, Cross Country, and Trans-Pennine as they were referred to at the time. Turning to the passenger rated four-wheeled vans of the era, some such as the FRUIT D were clearly of pre-nationalisation design, as were the SPVs that were inherited freight stock diagrams formerly INSUL-FISH and very much of LNER Faverdale vintage. Wouldn't count these as Mk.1. Nor the ex. LNER bogie CCTs. The B.R. standard CCT and HB were very much Mk.1, when you consider that they used all of the structural members, panels and fittings lifted out of the SC drawings, with a bit of pilfering of SW wagon stuff for the underframes. The GUVs were simply Mk.1 short frame, flat sided vehicles. If you go the other way there are a small number of 'Mk.1' design vehicles in the freight stock - particularly Ferry Motor Car Vans and bogie Scenery Vans that are pretty much CCT and GUVs with wagon numbers. When you look at stock totals, there were of course vehicles built new, but there were many conversions of existing vehicles of varying degrees, particularly when looking at the source vehicles for some of the EMUs. For more technical detail, and diagrams / photographs describing the above, Parkin's book is well worth a thorough read.

When converted from ordinary CLAYs, the CLAYHOODs were allocated diagram BR 1 / 13. However I've never seen a copy of it. The wagon depicted in UC 002 A / B weirdly seems to have gained an extra plank, as CLAYs were five-plank of well and truly GWR origin. Coincidence the GWR ones were diagram O 13 ? Just to add to this, when these were re-coded into the 'O' group in 1983, UC 002 A / B became OO 002 A / B ... fair enough. However, later OO 002 C and OO 002 D were added to cover the ones that had now been fitted with roller bearings (not a good move on something carrying loose powdered stone !) but these two later diagrams show them without hood / support bar but with AARKND of OOV H which would indicate CLAYHOOD. The inside height of these six-plank oddities is same as the original five plank B.R. 1 / 51 CLAY, so methinks a bit of drawing office licence ???

Thank you again. Getting into the weird stuff now. We were used to an eclectic mixture of steel carriers in the N.E. area, but clays and pig irons were more of two parts of the country I didn't get to see much of. Cheers for all your hard work. Much appreciated.

Thank you again. Missing ones could be an indication of all examples of that diagram being withdrawn or converted to something else, and the diagram becoming extinct before 1974, as the codes were originally allocated early around 1970 / 1971. Presumably any extinct diagrams wouldn't be drawn up.

Thanks for those. When you get round to the cattle vans, please can you look out also for the following that appear to have been deleted quite early on : VC 001B VC 006B VC 007A, B Cheers.

The mirrors originally fitted in Mk.1 coaches had an engraved B R monogram formed with the B reversed and abutting the script 'R'. Sorry, haven't got a photo' to hand but do have such a mirror that survived past all of the later 'arrows of indecision' branded replacements.

Apologies it's a long list !

Thank you for those. The diagrams that would have been in (B) part 3 were, in addition to the ones you have posted : RR 001A to RR 001N (excluding that there was no 'I' suffix, as per normal practice with these things). These were assorted Runner Wagons converted from Plate Wagons. Some of these codes were later re-used for similar vehicles, but not the same as the original diagrams. I have RR 001C, E, G that came much later but used different source vehicles. Of the original RR 001 series, these were recoded from SP 005A, 013A, 014A, B, 015A, B, C, 016A, 017A, 018A, B, C, D (not in that order though). Some of these SP you have posted already earlier. RT 004A was the rectangular bodied version of Diesel Brake Tender. For the S group, looking for : SO 001F and G SP 003A, B, F SP 004C, D, J SP 006B SP 007A SP 008A, B, C SP 009A SP 010A, B SP 012A SP 018A, B, C, D ST 002A, B, C ST 003B ST 004A ST 005A, B ST 006A, B ST 007A, B ST 008A ST 009A, F, G ST 010B ST011A, B SW 002A For the U group, looking for : UC 001A, B (these recoded OO 001A, B) UC 002A, B (these recoded OO 002A, B) UL 001A, B UP 001A, B, C, D UP 002A UP 003A US 001A, B US 002A UT 001A UT 002A, B, C UY 001A, B UZ 002B UZ 003A UZ 004A Now for the vans in the V group, looking for : VC 001A VC 002A, B VC 003A VC 004A VC 005A VC 006A VD 002A VF 001A, B VF 002A, B, C VF 003A VN 001A VP 002A VP 003A, B VP 005A VP 006A VP 007A VQ 001B VQ 003A VQ 004A VR 001A VR 002A, B VS 001A VS 002A VS 003A VS 004A, B, C VS 005A VV 001A VV 002A VV 003A VV 004A, B, C, D, E VV 005A, B, C VV 006A, B, C VV 007A VV 008A VV 009A, B, C, D VV 010A VV 011A VV 012A VV 013A VV 014A, B VV 015A, B VV 016A, B, C, D VV 017A VV 018A VV 019A VV 020A VV 023A VV 024A VV 025A VV 026A VV 027A, B VV 028A VV 029A VV 030A VV 031A VV 032A VV 033A VV 034A VV 035A VV 036A, B, C VV 037A VV 038A VW 001A, B, C, D VX 001A, B Could you also have a look for any of these please : MC 002A MC 003E MC 004A MC 007A MC 008A MC 010B MC 011B MC 012A MD 003B MD 006A MS 002H OH 003C (the original one, or as re-coded OW 003C, wooden body HYBAR) OH 004A original, or as re-coded OW 004A (wood body HYBAR) OH 019E or as re-coded OW 015D OH 020A OL 003A OS 005A OS 007A, B OS 009A Hope this all makes some sense. Please give me a shout if not.

When BR took TOPS it was 'adapted' somewhat to our particular operational needs. The BR usage of some of the data fields / codes sometimes don't correspond to the original American implementation. The CARKND is the three-letter code generally displayed on the side of a freight vehicle in the data panel along with the vehicle number. The CARKND is made up of two letters that identify the type of vehicle CKINDX (which I seem to recall was short for CARKND INDEX), followed by one letter BRAKTY which identifies the type of train brake. As mentioned earlier up thread, GENKOC is the first letter of the code and gives a rough idea of the grouping of vehicle types. B = Bogie Steel, C = Covered, O = Open, V = Van, etc. Beware that the second letter of the CKINDX only applies within its own GENKOC, so there's no correlation between the usage of A / B / C, and so on in the second character position other than pure coincidence. In some groups, particularly wagons, there was an attempt to carry over some indication of the old telegraphic code for the vehicle type. Hence for example in group B which was bogie bolsters, many of them had the second letter as the TEL CODE suffix : BA = Bogie Bolster A (remember them ?) or more latterly Bogie Steel AB for the more modern air-braked sorts, BD = Bogie Bolster D, and so on. As there can be many somewhat different designs of vehicle all with the same CKINDX or CARKND, an extra letter is added to make the four-letter AARKND. The meaning of this letter is unique to each CKINDX although there are some common themes albeit not universally applied. The generic 'basic' type is often given a last letter of 'C', with variations following on D, E, and so on. These variations could be different body types, different forms of vacuum brake, different owning or operating department, or many and various other differences. R could signify 'rebodied' as in the case of coal hoppers. 'M' could mean 'Metric' if applied to Bogie Steel AB, or 'Motorail' in the context of carflats, Milk Tanks were mostly 'M', or for MGR hoppers 'M' indicated fitted with canopy. Around the mid '90s there seemed to be a spate of displaying the AARKND on wagons, usually privately owned, usually as the usual three-letter CARKND with the extra suffix letter tagged on after a dash / hyphen. The two-letter CKINDX is also the first two characters of the Diagram Index for the vehicle, followed by a three digit number and one more letter. These are the pages in the vehicle diagram books on Barrowmore MRGs web-site. For each CKINDX, the number starts at 001 for revenue vehicles or sometimes 500 for service vehicles / departmentals if it's necessary to make the distinction. The final letter identifies a sub-type of the vehicle or a modification. The above applies to wagons / freight stock, but for passenger coaching stock there is a further system within TOPS called POIS (Passenger Operations Information System). Coaching stock is given a CKINDX code as with other stock, and has a BRAKTY, accordingly if you wanted to book a passenger coach into a freight train consist you could blast in its CARKND. So NAV would be a gangwayed brake, vac fitted. ABX would get you a dual-braked corridor compartment coach with a guard's brake. Freight train lists will output passenger coaches in this way. Here you're not worried if it's a first class, second / standard, or composite but you are hopefully going to make sure its brake is the right type for the train it's going in. POIS however is interested in the class of passenger accommodation and the type or 'mark' of the vehicle, so you take the CKINDX and add a number to signify class (1 = 1st, 2 = 2nd, 3 = 3rd ... no sorry ... composite !, 4 = unclassified, and 5 = no passenger accommodation = NPCCS), then a number or letter signifying the design 0 = pre-nationalisation, 1 = Mk.1, A = Mk.2A, G = Mk.3, the odd one out being Mk.2 which is weirdly Z, and not 2. So a Mk.2D TSO would be AC2D. This is displayed at the lower left of the end of the coach, or maybe higher up if it has a data panel.

If you could please that would be really helpful, and will be much appreciated. My two (B) stock books look to be reasonably complete up to the end of the 'O' group (but without the re-coded OH steel-bodied HIGHs and OW wooden bodied ones that replaced the original OH types. Barrowmore has book 320 parts 1 / 2 / 3 at issue revision 1, but not part 4 so stops around about the same place. There was a reasonable proportion of the 'S' group that did a better job of surviving into the '80s than the R / U or vac / unfitted vans. I could do you a list of the missing S diagrams if that would help save you some copying ?

The (B) series books came about with the initial introduction of TOPS in 1974. Locos received the same treatment, given numbers in the MT series (MT/25, MT/26 and MT/27). There was some reallocation of TOPS codes as the system started to get used. For example, ironstone hoppers recoded from HI to HJ. Then others to make better distinction between types - such as all open HIGHs started as OH, but later split to put the wooden bodied ones into OW and tidy up the remaining steel bodied examples in OH. Incidentally, if you wonder why brake vans were in group C, consider that they started as TOPS code CAB (= American caboose). When they settled on including the brake type letter this odd-one-out three letter TOPS code was changed to CA to make room for the brake type letter (O/P/V, etc.). The only other three letter TOPS codes were ROP = ropes and RSH = sheets. These were ignored when the R group used for running department vehicles - which is where you would have expected brake vans to reside. In 1981 a project was instigated in the D.M.&E.E. Drawing Office, to bring the rest of the stock into TOPS, hauled coaches and multiple units, etc. Part of this was the 'Revised Vehicle Diagram Book Numbering System' with all books now in one series of numbers. Presumably by then the (B) series books had grown to four parts cf. the original three, with the groups re-split accordingly. Some of the Book 320 Part 1 to 4 were newly printed ready-to-go, containing just those diagrams extant at 1981. There were also update kits to as you describe, change the covers of the corresponding (B) part to Book 320. At this point the stuff that expired during the '70s would be expunged. Hence no more Horse Boxes, Banana Vans, Cattle Vans (or re-use for Ale), Fruit, Meat, Fish, or Parcels Vans (that were ex fish vans). Also a lot of 12T ventilated vans. This is what I'm trying to fill in the missing blanks in groups R to V. A further project erupted in 1983 when the coaches were put onto TOPS 'properly'. In amongst this, a fair bit of recoding went on. Oh, what fun that set in motion. There was a further reprinting exercise thereafter to clean up the books for new issues. It was about this time my involvement in TOPS starts, so I've missed out on the earlier stuff. It appears that they never plucked up enough courage to document the Q or Z groups properly. I only ever remember the Q series having cross-references to drawings that were presumably general arrangement drawings, rather than the usual diagram book format. Fair enough there were hundreds of these but with only one or very few vehicle(s) of each diagram. The drawing office at Derby probably struggled to keep up. The departmental stock book 350 only seems to have got as far as the Y group bogie vehicles. At the start, all departmentals started out in group Z, but this was split up fairly early on to use Q for ex-coaching stock, and Y for bogie vehicles, leaving just the 4-wheel (or more accurately - rigid framed) in group Z. Not seen a book for these - no part 2 for book 350 ?

TOPS 'hours' were based on engine hours but with an applied conversion (fudge) factor, that varied over the years between 1.6 times to 1.8 times, reflecting experience gained at estimating the maintenance need compared to deterioration of equipment / component parts to achieve the desired reliability / availability figures. The exam schedule with 55 'hour' baseline applied to the general common-or-garden mainline diesel loco classes. There were some exceptions where intensive use or arduous service conditions mandated a schedule with a shorter baseline. I seem to remember it was 39 hours for Deltics ? Doesn't apply to AC electrics as these had their own schedule based on 'balanced work'. This has the content of the 'A' exam that must be done every time round, and a proportion of the work content of each of the other levels of exam. That way, each visit to the shops was expected to be of similar duration barring work arising, such as unplanned or unexpected defects being found. This strategy tended to be adopted for multiple units on intensive services. When you look at diesel shunters, in the same way as wagons, these we considered worked to a calendar, not service hours. That being, days / weeks / months. Simon : I do hope that means there's a Peak book in the pipeline to look forward to ?