Rods_of_Revolution Posted February 17, 2012 Share Posted February 17, 2012 This is something I have often wondered about and I was recently reminded about on another thread about pway trains. I have a Cornish layout under construction set around the mid 1980s. I have a mixture of stock, both air and vac braked. What I really want to know is how do I protoypically operate the both of them together? A common thing I have seen is a consist of Locomotive - Airbraked vehicles - Brake van - Vacbraked (running unfitted) vehicle - Brake van What are the rules? What ratio of vac vehicles can you operate unbraked to the number of fully brake air vehicles? Are there speed restrictions on the train? Do you need to sandwich the unbraked portion between two manned braked vans? Basically I'm after any information which allows me to run my layout prototypically, also I really like brake vans so the more I can justify the better! Many thanks, Kindest Regards, Jack Link to post Share on other sites More sharing options...
Edwin_m Posted February 17, 2012 Share Posted February 17, 2012 Except in a couple of special cases I don't think air and vacuum braked vehicles could be run in the same train with both types of brakes operating. The "fitted head" would be a number of wagons with the same brake type marshalled next to the loco, and any wagons with the "wrong" type of brake would have to run as unfitted in the rest of the train with no working continuous brake. A partially fitted train like this would always have a brake van as the last vehicle but would occasionally include other brake vans elsewhere in the train. You could include a "piped" wagon or brake van in the fitted part of the train. It would not itself have any continuous brake but would allow the continuous brakes to work on wagons further back, which is why some early air-braked wagons had through vacuum pipes. In this way you could run a certain number of piped wagons in a fully-fitted train, provided the last several wagons had working continuous brake. One special case was the Freightliner trains that ran for a while in Scotland with vacuum braked coaches and air-braked container flats - I don't recall how they did this but it's been mentioned on here before. When testing the (air) brakes on new wagons the test coach also ran with vacuum brakes, but I think the coach was dual-braked so used this arrangement only under possession, with transit moves being fully air braked. Link to post Share on other sites More sharing options...
TomJ Posted February 17, 2012 Share Posted February 17, 2012 There are a reasonably number of photos of Cornish clay trains with mixed braked trains, especially in the earlier 80s. As you know these trains need a brake van and usually whichever type of wagon was greater in number would be next to the engine so as to use their brakes as assistance. A brake van would be needed if only a single wagon with an alternate system was present as that wagon is effectively unfitted - the only exception being a through piped wagon with the fitted wagons behind acting as the brake. I have a photo of a 37, through piped cargowaggon (air braked) followed by a rake a vac fitted clayhoods. There are other Cornish excuses for a brake van. Trains to Ponts Mill were propelled from St Blazey so always had a brake van leading. All the pics I e seen of clayhoods on the Wenford branch include a van - presumable for the shunter to travel in (not allowed with driver in the single cab 08). This must have lead to interesting shunting with all the reversals. The There are a reasonably number of photos of Cornish clay trains with mixed braked trains, especially in the earlier 80s. As you know these trains need a brake can and usually whichever type of wagon was greater in number would be next to the engine so as to use their brakes as assistance. There are other Cornish excuses for a brake van. Trains to Ponts Mill were propelled from St Blazey so always had a brake van leading. All the pics I e seen of clayhoods on the Wenford branch include a van - presumable for the shunter to travel in (not allowed with driver in the single cab 08). This must have lead to interesting shunting with all the reversals. The other one I can think of is the trip to Par docks, again presumably for the shunter - manual gates to open. HTH Link to post Share on other sites More sharing options...
dmustu Posted February 17, 2012 Share Posted February 17, 2012 It was possible for an air braked train to assist a vacuum braked train (and vice versa) in the rear providing the assisting loco was duel braked. It was possible to haul a train with one brake type, whilst pushing one of the other type, and providing braking for the whole train. Also, if a vac braked train is to be hauled by an air braked loco, a duel braked loco can be placed in between the leading loco and the train to convert the air brake to vacuum, something that is done quite often on preserved railways. As for run of the mill trains though, as mentioned above, a portion of the train would have to be unbraked, with a brake van provided at the rear of the train. Link to post Share on other sites More sharing options...
Rods_of_Revolution Posted February 17, 2012 Author Share Posted February 17, 2012 So it was acceptable to have a locomotive, several airbraked vehicles and then vacbraked vehicles running as if they were unfitted provided there was a brakevan at the back to arrest the unfitted portion if it broke away? Kindest Regards, Jack Link to post Share on other sites More sharing options...
RMweb Gold The Stationmaster Posted February 17, 2012 RMweb Gold Share Posted February 17, 2012 So it was acceptable to have a locomotive, several airbraked vehicles and then vacbraked vehicles running as if they were unfitted provided there was a brakevan at the back to arrest the unfitted portion if it broke away? Jack Yes - provided the fitted bit had sufficient Brake Force; it just ran as a Partially Fitted Train. Link to post Share on other sites More sharing options...
Rods_of_Revolution Posted February 17, 2012 Author Share Posted February 17, 2012 Yes - provided the fitted bit had sufficient Brake Force; it just ran as a Partially Fitted Train. Could you give me a rough guide as to what ratio tons of fitted to tons of unfitted would look right in a train? Many thanks, Jack Link to post Share on other sites More sharing options...
Rivercider Posted February 17, 2012 Share Posted February 17, 2012 Could you give me a rough guide as to what ratio tons of fitted to tons of unfitted would look right in a train? Many thanks, Jack This starts to get very complex, and depends upon various factors, such as the gradients of the route the train takes and the maximum permitted speed of the train. By the mid 1980s trains in Cornwall were fully fitted ( except possibly by special exemption). However as a very rough guide, and trying to remember how to read my old 1988 Working Manual, the following applies Par - Lostwithiel, Class 37 can take, 34 loaded clayhoods @ 19 tonnes = 646t plus loco 105t equals total weight 751t to run at 45mph it would need 160t brake force, to run at 60mph the same train would need 230t brake force. A class 37 provides 50t brake force, each clayhood approx 4t bf (34 X 4 =136t) = total 186t bf, so OK to run at 45mph but not 60mph. This is academic as I think the clayhoods were max speed 45? or 50? anyway. The TOPS trainlist would work that out for you. hth cheers Link to post Share on other sites More sharing options...
roythebus Posted February 18, 2012 Share Posted February 18, 2012 What's been said above about mixing brake types is correct. i don't know of any instances of trains being run with "mixed" brakes operating as it was just not done! the only exception I'm aware of was for SR MLVs to haul one or two vac braked parcel vans, and again that was a rarity. As for the portion of fitted/unfitted in a train, you can have any number, but as decreasing maximum speeds. an unfitted train would typically be limited to 35 or 25 mph depending on load etc. It is indeed very complex! Link to post Share on other sites More sharing options...
Rods_of_Revolution Posted February 18, 2012 Author Share Posted February 18, 2012 Thanks for the help guys, I guess running an unfitted train wouldn't be much of an issue in Cornwall as most of the clay branches had a speed limits of around 30mph, with the assistance of airbraked vehicles in the consist the speed wouldn't be too restricted anyway. So if I wanted to run a rake of 12 clayhoods and a VDA, the clayhoods would lead, followed by the effectively unfitted VDA and then a brakevan? The TOPS Trainlist would then dictate the operating speeds based upon the consist? Many thanks, Jack Link to post Share on other sites More sharing options...
Fat Controller Posted February 18, 2012 Share Posted February 18, 2012 What's been said above about mixing brake types is correct. i don't know of any instances of trains being run with "mixed" brakes operating as it was just not done! the only exception I'm aware of was for SR MLVs to haul one or two vac braked parcel vans, and again that was a rarity. As for the portion of fitted/unfitted in a train, you can have any number, but as decreasing maximum speeds. an unfitted train would typically be limited to 35 or 25 mph depending on load etc. It is indeed very complex! There was an example of mixed air and vacuum braked working, I believe, but very limited in application- the inclusion of an air-braked/vacuum-piped Freightliner flat (FJB) in an otherwise vacuum-fitted passenger service from Inverness to the Far North. To further complicate things, I believe the wagon had a through steam pipe. A pool of three wagons were dedicated to this traffic- south of Inverness, they were included in Speedlink services. Link to post Share on other sites More sharing options...
Poor Old Bruce Posted February 18, 2012 Share Posted February 18, 2012 As long as the last vehicle of the train has a working automatic brake you could, in theory, run without a brake van at the rear. Around 1970ish I took a train from Derby Research to London, ECML to Glasgow, WCML back to London, GWML to Bristol then back to Derby. The train consisted of a vacuum braked Lab Coach (Ex LMS Porthole BSK) with a hose pipe strapped to the solebar to provide the air brake for a COV AB test vehicle. The Lab Coach was effectively unbraked (handbrake only) with train braking being provided by the loco and van. I can't remember whether there was an emergency brake valve in the coach or not but there was telephone communication between the coach and loco. We were allowed to run at 75 mph but because we were only part fitted we ran as a Class 6. The only problems that caused were coming out of Glasgow Mossend, where we had stabled, the singalman had not got (or read) the Special Notice so let out a Class 2 stopper to Carstairs in front of us and on the last bit from Birmingham to Derby when we were again behind a slower train. As we needed 75 for the data gathering I consulted with the PSB and sat on the main line at Water Orton for a while until the preceeding train had got away a bit and before we were holding up anything else. Probably wouldn't get away with it now. Link to post Share on other sites More sharing options...
Rivercider Posted February 18, 2012 Share Posted February 18, 2012 Thanks for the help guys, I guess running an unfitted train wouldn't be much of an issue in Cornwall as most of the clay branches had a speed limits of around 30mph, with the assistance of airbraked vehicles in the consist the speed wouldn't be too restricted anyway. So if I wanted to run a rake of 12 clayhoods and a VDA, the clayhoods would lead, followed by the effectively unfitted VDA and then a brakevan? The TOPS Trainlist would then dictate the operating speeds based upon the consist? Many thanks, Jack This isn't Cornwall, but it is clay traffic, from Marsh Mills. 08941 has charge of a VDA and about 8 clayfits and BV. In this instance the train would be air braked with the VDA piped up, the clayfits effectively unfitted. As you say, at low speed the brake force of loco (19t bf) and VDA (21t bf) would be ample. 08941 at Tavistock Jn with traffic from Marsh Mills, 22/9/80. cheers Link to post Share on other sites More sharing options...
RMweb Gold Ramblin Rich Posted February 18, 2012 RMweb Gold Share Posted February 18, 2012 Jack, here's a nice example on the North Devon line of a similar kind of set up to what you are thinking of - vac fitted "clayliner" opens, vac fitted vans, possibly a "lowfit", then a (normally airbraked) SPA steel open running unfitted, then brakevan. Link to post Share on other sites More sharing options...
Rivercider Posted February 18, 2012 Share Posted February 18, 2012 Basically I'm after any information which allows me to run my layout prototypically, also I really like brake vans so the more I can justify the better! Many thanks, Kindest Regards, Jack TomJ has already mentioned the Pontsmill trip worked by a class 08 with a brake van, and the Wenford Bridge working. The May 1975 local trip booklet shows the Wenford trip as Trip No.20 departing St. Blazey l//d at 08//15 (SX) as 0B90, arriving Bodmin Rd 08//45, then work trip as 7B90 until:- depart Bodmin Rd as 7B90 at 14.15 (SX) arriving back at St. Blazey at 15.00 (The 08 was permitted to convey 25 loaded clayhoods from Bodmin Rd to Lostwithiel according to a May 1980 Freight Train Loads Booklet) I photoed 08113 twice, in Nov 1982 and again in April 1983 as it was returning mainline to St. Blazey with its BV 08113 with brake van in tow leaves Bodmin Road after working on the Wenford Bridge trip, 15/4/83. cheers Link to post Share on other sites More sharing options...
Rods_of_Revolution Posted February 19, 2012 Author Share Posted February 19, 2012 Thanks guys, the photographs are especially nice to see, as it's no longer possible see to such quaint trains. Thanks Kevin for the details on the Bodmin trips, an interesting working especially with all the reversals! Many thanks, Jack Link to post Share on other sites More sharing options...
Pennine MC Posted February 19, 2012 Share Posted February 19, 2012 Jack, here's a nice example on the North Devon line of a similar kind of set up to what you are thinking of - vac fitted "clayliner" opens, vac fitted vans, possibly a "lowfit", then a (normally airbraked) SPA steel open running unfitted, then brakevan. I think your 'lowfit' is a vac fitted 22T Plate. Lovely pic, though but Link to post Share on other sites More sharing options...
TomJ Posted February 19, 2012 Share Posted February 19, 2012 The Bodmin/Wenford trains were interesting because the 37s were banned from the Boscarne-Wenford section but a 08 could only cope with eight loaded clayhoods on the climb from Boacarne-Bodmin. So usual practice was, I believe, for an 08, empty wagons and BV to leave St Blazey for Wenford (a total of four reversals!). The 08 would bring a string a loaded wagons to Boscarne where a 37 would take over. The 08 and BV would work light back to St Blazey. If loads were light then the 08 would work the train through. Loads of intersting modelling possibilities there! Another example of a BV working in Cornwall were the very rare spoil trains to St Dennis junction. There's a couple of pics in a John Vaughan book, either grampus or turbot wagons (avaliable as N gauge kits) and a BV Link to post Share on other sites More sharing options...
woodyfox Posted February 19, 2012 Share Posted February 19, 2012 Although not freight I used to drive a train back in the late 80's/early 90's. It ran M-F from Sherbourne to Waterloo and consisted of 4TC (air), Class 33 (pushing) and a BG/GUV (vac) on the rear. If you had the 4TC on EP brake (electro-pneumatic) then technically you had 3 brakes on one train... ... I forget the technology on the 33 that made all this possible, IIRC it might have been either the Westcode Unit or the equalisation and discharge valve... ...great technology for it's age though... Regards Stu Link to post Share on other sites More sharing options...
retbsignalman Posted February 19, 2012 Share Posted February 19, 2012 There was an example of mixed air and vacuum braked working, I believe, but very limited in application- the inclusion of an air-braked/vacuum-piped Freightliner flat (FJB) in an otherwise vacuum-fitted passenger service from Inverness to the Far North. To further complicate things, I believe the wagon had a through steam pipe. A pool of three wagons were dedicated to this traffic- south of Inverness, they were included in Speedlink services. Hi! I remember this working well, it was a bit of a squeeze especially if the loco had miniature ploughs!! Air and vacuum bags tied up along with the steam bag too, oh, and those very large diameter buffers on the wagon - just as well there wasnt a gangway to wrestle with too ( I was considerably thinner as a shunter then than I am now as a signalman)! As you'd expect, when the driver applied the train brake, it applied in equal amounts to both the flat on air and the coaches on vacuum, without the risk of wheelflats. The traffic ran from Aberdeen to Wick, so once the stock was taken away, the loco that arrived from Aberdeen would take the wagon round to the north platforms and attach it to the front of the evening Wick service, and in the southbound direction, once the stock was taken away, the engine from Wick would take the wagon round to the south side platforms and attach it to an Aberdeen service. On arrival at Aberdeen, the train loco took the wagon to Guild St yard where there was a container gantry crane to unload/load it. At Wick, the wagon was placed in the yard on arrival during a double run round move (propel onto the single line, detach coaches, run round wagon, shunt into siding, collect coaches and return to platform, run round again!) Hope this helps Graeme Link to post Share on other sites More sharing options...
roythebus Posted February 19, 2012 Share Posted February 19, 2012 Although not freight I used to drive a train back in the late 80's/early 90's. It ran M-F from Sherbourne to Waterloo and consisted of 4TC (air), Class 33 (pushing) and a BG/GUV (vac) on the rear. If you had the 4TC on EP brake (electro-pneumatic) then technically you had 3 brakes on one train... ... I forget the technology on the 33 that made all this possible, IIRC it might have been either the Westcode Unit or the equalisation and discharge valve... ...great technology for it's age though... Regards Stu No Westcode, the equalisation/discharge valve. A similar unit was fitted in the MLVs so I was told. Link to post Share on other sites More sharing options...
Rods_of_Revolution Posted February 20, 2012 Author Share Posted February 20, 2012 Assuming that guards were not allowed to travel in the same cab as the driver, does this mean any single cab locomotive would always have required a brake van? So even a full fitted Class 08 hauled train, or a single Class 20 hauled train would require a brake van for the guard to travel in? Thanks, Jack Link to post Share on other sites More sharing options...
Guest stuartp Posted February 20, 2012 Share Posted February 20, 2012 Can't answer for 08s (I think the answer is 'yes' but I can't find an example). For 20s it's definately 'yes', even on double-headed 20s, at least until well into the blue period as there was no brake valve on the secondman's side for the guard to operate. (Guard's weren't allowed to touch the driver's brake valve, of which there were two in each cab, because that was the driver's job*. Long live restrictive trade practices.) Brake vans were required until the 20s were retrofitted with emergency brake plungers in (I think) the 1980s but someone else will need to confirm the date for you. (*Story involving a derailed EMU in a tunnel, a broken wrist and a sacking available if anyone wants it, but it's outside the scope of this thread). Link to post Share on other sites More sharing options...
RMweb Gold The Stationmaster Posted February 20, 2012 RMweb Gold Share Posted February 20, 2012 Assuming that guards were not allowed to travel in the same cab as the driver, does this mean any single cab locomotive would always have required a brake van? So even a full fitted Class 08 hauled train, or a single Class 20 hauled train would require a brake van for the guard to travel in? Thanks, Jack The answer for 08s was definitely 'yes - brakevan required' and i doubt this would have changed before most 08 trip working had vanished. Interesting point here tho' - if you were a Guard would you prefer to travel in the cab of the loco or in a brakevan which, as long as it was 'draught-proofed', was probably a more comfy option i reckon, and definitely a lot more roomy. Edit to correct typo Link to post Share on other sites More sharing options...
Pennine MC Posted February 20, 2012 Share Posted February 20, 2012 Assuming that guards were not allowed to travel in the same cab as the driver, does this mean any single cab locomotive would always have required a brake van? So even a full fitted Class 08 hauled train, or a single Class 20 hauled train would require a brake van for the guard to travel in? Thought this would be coming There's an item on my Wordpress blog (link below, see the 'Traditions in Decline' page) that might be of interest, as well as the posts above. Link to post Share on other sites More sharing options...
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