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Hitchin Junction

London Tram track spacing and minimum radius

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Anyone know the figures for the above? I'm getting ready to make up some old 4mm London E1 kits and I want to make sure I can run them realistically and around tight corners, but without any collisions on curves.

 

Tim

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Hi. 

 

 

I cant answer the spacing between rails question but I have some ideas re curve radius.

 

is it necessary to use the minimum...?

 

the great benefit you have modelling London is that most of the streets in the centre are unchanged.  THe street furniture and lane marking may change but the overall shape of the junction is dictated by the buildings and many of the city buildings are still there.

 

If you identify some well photographed London tram junctions, find them on google maps today, change to satellite view and enlarge, then with a right click of the mouse select measuring tool and then by clicking between two points on the map you can measure and map out the junction.  Use an old photograph of the junction to see positioning, maybe calling up google street view to compare with today.  There will also be areal photographs of London which can be zoomed that do show trams and tramways.  I think the website is Britain from above, (if I come out to check I'm bound to lose the post)

 

i guess im saying don't do minimum, do normal.

 

andy

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To add to Andy's ideas, the old-maps website is useful, as they have large scale maps from both the start and end of trams in London. This snippet, courtesy of their website, shows the track arrangement at St George's Circus in Lambeth, and other locations will reveal sharper or more complex layouts; suggestions welcome.

 

image.jpeg.83035424163608e58490f6c97d7039de.jpeg

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Tim, probably the minimum for conduit tracks can be determined by taking the width of a LCC E/1 class car at 6'9" on each parallel track plus the width of a 'fat' policeman between!   I do say the  absolute minimum!!!   Laying of tracks had to take into account the utility pipes beneath the deeper 'slab' required for conduit track so in some places without islands tracks were seen to be slightly further apart.   So beware introducing Felthams on to your line.   When these were transferred to Streatham depot, the Met Police issued instructions as to which streets policemen could not perform traffic control duties between tram tracks as the Felthams were 7'3" wide.   There were instructions as to where Felthams were not to go except for special individual runs such as transfer from their north and south London depots to Charlton CRD.   Their greater end overhang being a further limitation.

 

I use both Simon Dawson's 'Recreation21' conduit and overhead track as the sides of the sections incorporate the compulsory 18" tramway margin.   Then you can allow for the policemen/islands/utility manhole covers in between to suit your space.

 

For the production of BEC and/or Tower E/1s you may be interested in the 'plug-in' mechanism/body swap concept I used for John Clarke's "West Croydon" layout.   This is illustrated on the forum "Brixton Hill Tram Depot".   You are very welcome to display any photos you take of them on that forum whether or not their prototypes operated from Streatham depot and its annex at Brixton Hill.   Hope all goes well, Colin. 

 

 

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thanks for that Colin. The geometry and measurements I used were initially based on width of standard OO/HO sleepered track and the geometry of other model tram track systems such as the old Hartel and Tillig now, where the curves are 20cm and 25cm radius. This was to make sure any 'r2r'tram models would run O. I had not thought about fat policemen. Will have to look for a model figure to put on my tram layout!

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Simon, you had an insert that went between double tracks did you not?   That was sufficient for the fattest not only of policemen but also the regulators!!!   I say regulators because I have fond memories of the regular regulator at Kennington Horns junction.   He was portly!!!   He stood on the Elephant/Lambeth corner of the junction next to "The Horns" PH.   He was so 'lubricated' that he could 'shoot' from talking to a driver in Kennington Park Road to another in the Kennington Road as he sorted out the 4s and 18s from Westminster to get them in order with the 2s and 16s from Blackfriars to continue south.   And all this was done between moving road traffic with an eye on the traffic lights!!!   At the start of the evening rush-hour, I used to return home from a day on the Embankment on the 18,up front in my favourite seat on a Feltham, join the queue for those lights and be entertained by him.   The telephone bell would start to ring as he was in mid-flight and he had to juggle where he was and what to do next!   I understand his job became virtually impossible when the trams were replaced by buses (now in two lanes to the lights!) and the volume of road traffic immediately increased.   All the best, Colin.

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I followed up on the picture measuring idea using a web photo I found of the down incline into the Kingsway underpass. That gave a centre clearance width of around 47 inches between two standard gauges of 56.5 inches.  So the Twin Tracks centre to centre comes out at say 104 inches, or 8ft 8".   That's definitely not a safe space for even a skinny human between two cars, but should look fine on a model. Curves of course are different matter.

 

The unexpected fly in the realism ointment however is the 4mm "00" narrower gauge.  The real track shows up as a wider gauge than the spacing, whereas, using 16.5 mm "00" track, it's obviously the other way round. I'm not sure there's an easy answer to that.

 

Tim

 

 

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1 hour ago, Hitchin Junction said:

I followed up on the picture measuring idea using a web photo I found of the down incline into the Kingsway underpass. That gave a centre clearance width of around 47 inches between two standard gauges of 56.5 inches.  So the Twin Tracks centre to centre comes out at say 104 inches, or 8ft 8".   That's definitely not a safe space for even a skinny human between two cars, but should look fine on a model. Curves of course are different matter.

 

The unexpected fly in the realism ointment however is the 4mm "00" narrower gauge.  The real track shows up as a wider gauge than the spacing, whereas, using 16.5 mm "00" track, it's obviously the other way round. I'm not sure there's an easy answer to that.

 

Tim

 

 

Not exactly as accessable as along a road, so suspect it is minimum they could get away with.

Track centre to track centre would be same what ever gauge is used for 4mm scale, as width of trams is still the same.

 

If anyone is considering EM or P4, then the trams are pretty narrow and I have heard it can be difficult to fit wheels and mechanisms. I had a similar problem modelling London trams in HO scale, and kept mechanism very basic, ie dummy bogies.

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Tim, do NOT use the dimensions by the tracks in the Kingsway Subway.   The Subway was on private land with the only public access being pedestrian at the two stations.   Therefore you must work on photos of public thoroughfares where tracks would have been laid subject to the provisions set out in the relevant Acts of Parliament.   The provisions usually referred to the Board of Trade later Ministry of Transport general specifications much of which went back to the Tramways Act, 1870 - hence the 18" margin either side of the track to cater for the wear to the roadway of the hooves of a two-horse tram.

 

You and Simon are quite right about "narrowness".   16.5mm. gauge is of course 4' 1 1/2" and that is why I model the British 'four-footers' (and H0 for my continental ones) outside of my London cars - they look better from the ends!!!   I have just sent my plinth with 18.83mm. track to the T&LRS's National Model Tram Collection,for posterity.   I built it from PC Models grooved track and their adhesive backed granite sett sheet to prove to myself that when BEC kit 14 was released the revised model Feltham width looked correct over it compared with 16.5mm.   Even with the then help of members of the fledging P4 Society, I ran into the thickness of the white metal saloon sides and truck sides needing so much filing thinner if the car was not to ride too high to allow bogie swing.   So I have tolerated 16.5mm, ever since purely for my London cars.

 

By the way, I am just adding more posts on constructing kits of London cars on the RMweb "Brixton Hill Tram Depot" thread.   Colin.    

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I forgot to add that the Kingsway Subway track widths were of course laid by the LCC based on Edwardian dimensions.   The width problem in the Subway really showed up in the 1934 trialling the passage of Felthams through it for them to reach south-side initially for their overhauls being transferred from Hendon to Charlton in the summer of 1936 and then in the following autumn the start of transferring them all to Streatham depot.   Their greater end overhangs meant very careful driving through the curved single tunnel sections under Aldwych!!!   Although of metal construction, Felthams were not permitted through the Subway in passenger service - not even for chartering to LRTL members!!!   This helps to understand why "Bluebird" became the accepted standard future car for London and not the Feltham design.   I cannot recall anyone commenting on whether the shorter Feltham design for Walthamstow would have passed easily through the Subway. 

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9 hours ago, coline33 said:

Although of metal construction, Felthams were not permitted through the Subway in passenger service - not even for chartering to LRTL members!!! This helps to understand why "Bluebird" became the accepted standard future car for London and not the Feltham design.

I'm confused here, "Bluebird" is of metal construction and surely the Feltham was the chosen design.

 

Nigel L

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No confusion, Nigel, when you put it into timing of events - in fact you have two chosen designs both of which never reached the 1000 "Bluebirds" foreseen by LCC and 350 Felthams foreseen by LUT/MET and possibly a dozen shorter ones for a proposed joint MET/ Walthamstow tram service (LPTB introduced this service with trolleybuses).   

 

The regulations for the Subway from the start were that only metal bodied trams were to be used.   The LCC did get authority to permit wooden bodied trams to pass through provided they were not in passenger service when the Subway was enlarged for double-deckers.   The Felthams were introduced by the Underground Group of companies, who did not have any services through their competitor's Subway, and that was their chosen design for their future.   In fact the first experimental Feltham although conduit equipped had a wheel-base longer that the LCC standard which in the end was its downfall in 1936/37.   The second experimental had its overall wheel-base reduced to LCC standard to permit regular use on the LCC/MET joint services 21/29 - this was fortunate also in that this and the production Felthams could be accommodated on an LCC depot traverser but in the transfer to Streatham depot from 1936, the roof supports of the traverser hall had to be re-positioned to accept the extra length of a Feltham.   At the same time the Felthams were being developed by LUT/MET, the LCC enlarged the Subway for double-deckers so metal bodied cars were then introduced as a standard LCC car to meet their system's dimensions.   Hence the width of the E/3 and HR/2 classes continued to give 2+1 transverse seating in the lower saloon compared with the wider Feltham with its 2+2 seating - the extra 6" allowing this.   The LCC aware of the impact the revolutionary Feltham was having in attracting passengers, decided to build a more modern looking design of metal bodied car with similar features,but not all, that they could get into a car length slightly more that the E/3 and HR/2 to still make it able to traverse the whole LCC system and introduce air braking as with the Felthams.   "Bluebird" was the forerunner of a replacement fleet for the aging E/1s and we know that Sinclair had discussed with manufacturers an initial order for 100 cars as the chosen design for operating initially the 16/18, and Subway services 31,33,35 and 35A .   So the LCC's chosen design in 1932 for the future Subway cars was "Bluebird".   It was not until LPTB was formed and Thomas (from LCC) took full control of London's tramways that putting Felthams through the Subway was going to become a necessity but the clearances were so tight that safety issues restricted them to running 'light'.   By 1934, the LPTB had decided to develope the trolleybus as a tram replacement leaving Sinclair to cease the "Bluebird" project.   During 1934 one possibly two ex-MET Felthams were tested for clearances in the Subway and to find the most suitable routing to Charlton CRD.   We know that one Feltham still in the company livery was seen in Streatham confirming the date of the trials.   Needless-to-say London Transport never had a chosen design of tram, only attempts to make E/1s look more attractive or resemble "Bluebird"!!!   

 

I have elaborated my response to help others unaware of the background, Colin.

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Tim, I have decided to build a 40" x 20" circular double track conduit layout.   The track on the lengthwise display side will be code 100 rail within Recreation21 sections going into Peco Streamline with Peco's smallest radius points in the other half which will be the fiddle yard.   I want a simple life so no overhead, no paved point work, simple electric circuits to have 4 trams at a time in the display area and a 'manual' fiddle yard!!!   Probably the easiest design of layout for your E/1s.

 

Simon, order placed - wished the conduit tracks stood out better in your shop!

 

Nigel, I will be posting more on modelling Feltham experimentals on the "Brixton Hill tram depot" thread if Felthams inspire you.   "Bluebird" will follow once I have saved up for the 3D print!!!   Kind regards, Colin.

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1 hour ago, coline33 said:

Tim, I have decided to build a 40" x 20" circular double track conduit layout. 

 

I think you are somewhat answering my radius question. For your 20 " ends, your outer track has to be 9" radius or smaller, and the inner therefore around 1.5" radius less than that, to clear two E1's passing.  That would definitely show up the difference between trams and model trains that i'm looking for. 

 

Tim

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Tim, when years ago Simon was researching the dimensions for his Recreation21 system, a concensus was held with David Voice, myself and others in the Sub-Seven Modelling section of T&LRS in respect of minimum standards for 4mm. scale British operation.   Not only did we look at what happened in reality but also what were the limits of the mechanisms on offer in relation to bogie swing.   We concentrated on getting the inner curve right for bogie operation.   (Four wheelers of course can grind round much sharper curves!)   If that was right then given the end overhangs the outer curve would be OK.   Overhangs on Swansea & Mumbles, Blackpool Coronations and Felthams were seen as probably the worst a modeller would encounter.   Also the easier ability of a derailment with a maximum-traction bogie was taken into account.   Hence the 204 for inner and 250 for outer has become acceptable.   One thing I am not sure of about your E/1 kits, are they plastic or white-metal please?   I have E/1s in both materials and naturally weight becomes a factor in providing tractive-effort against resistance which increases as the curve gets sharper - which comes down to what I know as the 'angle of attack'!!!

 

If you have to have really sharp bends and steep gradients that bogie mechs will not take, then John Howe's London tram models successfully used four wheel mechs behind the dummy bogie sides.   Colin.

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I am puzzled that a 4w chassis will get round a tight curve more easily than two short wheelbase bogies.

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Joseph, yes in scale 1:1 when there is no skirting but In 1:76 scale the problem is the total size of a motor bogie within the limited space and width in the lower saloon together with the width of the plastic or white-metal saloon waist panels preventing bogie swing.   In reality even Leeds had a problem with "Bluebird" which had to have cut-outs before going into service.   My original Hamo standard German four wheeler had a 40mm, wheel base and could grind round 6" curves which was good for cleaning the wheels!!!   There is no way that my E/1s could do the same they would derail.

 

One morning going to work on my regular 0804 (run 34) tram I detected a flat and noted it.   At lunchtime I specifically caught the car for a run round the Croydon loop to feel if the flat had got worse.   The flat had completely disappeared.   As I had copy of the duty sheet for run 34, I was able to see that since my first journey it had done three round trips of line 3 with all its sharp bends.   So three runs from Croydon to New Addington should save use of the wheel profiling lathe!!!   To me the distance between bogie/truck centres on the CR4000s is the greatest they can go on that system's track - wheel squeal does become unacceptable on the driest of days!!!   The Stadlers, which are literally three four-wheelers joined together, give a very jerky ride on our sharp bends and the unpleasant ride up front is typical of that I have experienced on all four wheelers that I have ridden around the world.      

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thanks Colin. One design that might interst some is a cut down version of my inset track. Basically just  something to hold rail in position. Takes code 100 rail and found by chance that with rail inseted can be bent to tight radius.

http://www.rue-d-etropal.com/3D-printing/track-parts/inset-track-parts.htm

 

Could be used for any gauge. Insert rai, bend, and superglue down, but make sure rail is not glued in place.

 

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Colin,

 

Re the radius, sorry, I took your 20 x40 board size literally. I always think of track radius as at the track center line. 

 

My E1's hail from Tower Models a long (long) time ago. So they are the plastic ones. But I'm going to try cooking up my own chassis, so turning radius and weight will be pretty much what I end up making them as.  Since I'd like to acquire some of the modern Euro style trams eventually, I'm going to stick with 16.5 mm gauge and perhaps run them closer on the straights, to make the spacing look more London like. But I do want to stretch the layout out longer than just a plain oval, so that I can have some typical fancy tram pointwork and 2 or 3 different routes. 

 

I don't have any 4 wheelers, so I've not seen the rail climbing issue. But it does seem strange that they would have less of a problem than free turning bogies on curves.

 

Tim

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My apologises, Tim, but I should have typed 40" x 23 1/2" as my board size that extra few inches makes all the difference on curvature!   As I found out yesterday!!!   I too always take the radii on track centres.

 

Good I recognise your E/1s!   The enclosed version perfectly makes ex-Walthamstow 2nd series E/1 2054 for pre- or post-war eras.   As the TLRS Sub-Seven Secretary at the time as was asked by David Boyle for help so I selected that number for the transfer sheet when he started his plastic kit tram range.   Although as Secretary I was open to helping anyone producing kits, the fact that I had directly helped a 'competitor' caused Frank Vescoe to end the relationship with me.   That was despite my pointing out that the detail of the BEC kits was superior to the Tower equivalents.   If you have any open fronted kits then I recommend these to be best for major alteration - the enclosed fronted ones are best for just altering the windscreens to suit the ex-Croydon, East Ham and Walthamstow first series E/1s.

 

Now I read that you are thinking of introducing H0 in the future.   What using the same tracks?   If you are and you go for the conduit track then your modern Euros will have to be for 'ground pick-up' (with pantograph down) which certainly on Recreation21 conduit track the conduit can be disguised for today's version of 'ground pick-up'.   From what I see of second generation systems the space between tracks is wider than first generation as the 2.6m. wide is becoming the minimum norm.   Hard to believe that the 1930's saw the introduction of the 100" wide PCCs!   At Blackpool Mr. Luff had the foresight to widen the central space as tracks were relaid.   Do not make lines too bendy for articulated trams - as I had to point out to Croydon Council's planners in 1990 their first draft of Sandilands junction would have increased maintenance costs on the increased wear and tear of the articulations.   They took heed on that aspect in the revision but seemingly failed to draw attention to my request that "San Francisco Auto Control" should be demanded on the approach from the tunnel (my 1998 attempt got a response of investment capped and risk assessment shows a highly unlikely issue!!!).   My concern was a repeat of the cause of the Moorgate tragedy, because of the high speed approach to all three sharp bends on line 3.  Fortunately at Sandilands the overhead is span wire but H-girder posts around the other two would cause a 'bacon-slicer' effect to a tram derailing at speed there.   Good driving techniques and signage will never overcome a staff suicide.   I have had an operator drive a Boeing artic with the controls at 50mph through the San Francisco tunnel with this system.   Attempting to pass the zero board at 10mph the on-board computer which had automatically reduced the speed to 35mph and then 10mph., applied the electro-magnetic brakes with full force and we stopped before entering a road junction.   In 1948 I had the experience of the same emergency brake application on a Feltham, I was the only passenger but the car had to terminate at the next crossover as the conductress found herself in mid-air coming down the front stairs and needed treatment.   The fully loarded Boeing had polished plywood seats so the passengers all slid forward but the standing passengers had no problem they were tightly packed!!!   Today on Tramlink, once the emergency brake is applied and the car is stationary, the driver must leave his cab and go through the car so see if anyone has been affected. 

 

Next week, I will photo my conduit sections to give you an idea of the insulator hatch spacing and plough hatch locations.   They are not too different to those found on cable tramways - if you want to go that far back!!!   

 

Wishing you all a happy hot Easter, Colin.

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On 20/04/2019 at 10:09, coline33 said:

Next week, I will photo my conduit sections to give you an idea of the insulator hatch spacing and plough hatch locations.   They are not too different to those found on cable tramways - if you want to go that far back!!!   

The insulators were spaced at 15 foot intervals, and originally, each set had a hatch. However, as experience with the conduit system grew, it was found that having an access hatch at each location was unnecessary; the access pits were retained, but instead of openable covers, they were plated over and buried under the setts, the giveaway as to their location being that the setts immediately above each location were laid parallel with the slot instead of transversely. The conduit was also provided with drainage sumps every 120 feet, and these would have had access covers through which the cleaning "spade" could be inserted, and the detritus extracted. Access hatches for the extraction of collector ploughs were located at every section break, ie every half mile, and on the approach side of junction work.

A useful work on the subject of current collection methods in general, including the various conduit systems, is that by Messrs. Baddeley and Oakley entitled "Current Collection Methods for Tramway & Trolleybus Systems", published privately in 1975 by the authors but available (at least when I got my copy) via the Tramway & Light Railway Society, ISBN number 0 903479 04 4.

 

Jim

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On 20/04/2019 at 10:09, coline33 said:

 Today on Tramlink, once the emergency brake is applied and the car is stationary, the driver must leave his cab and go through the car so see if anyone has been affected.

From memory, that was actually a requirement imposed voluntarily by a typically risk-averse operator, rather than in response to any edict from HM Railway Inspectorate or TCL. That said, HMRI were thoroughly appreciative of the need to strike a balance in the standards and guidance for the design and construction of tramway vehicles between the risks to the person/vehicle in the path of the tram and the risks of injury to the passengers, of whom there was generally a greater number.

 

On 20/04/2019 at 10:09, coline33 said:

They took heed on that aspect in the revision but seemingly failed to draw attention to my request that "San Francisco Auto Control" should be demanded on the approach from the tunnel (my 1998 attempt got a response of investment capped and risk assessment shows a highly unlikely issue!!!). 

Interesting. A similar, but more passive, approach on my part post opening to provide advance signage of hazards (not specifically in relation to Sandilands) was met with a disinterested response from the Inspectorate and the operators on the grounds that, unlike the common motorist, tram drivers were expected to have sufficient route knowledge to anticipate these hazards.

 

Jim

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10 hours ago, jim.snowdon said:

The insulators were spaced at 15 foot intervals, and originally, each set had a hatch. However, as experience with the conduit system grew, it was found that having an access hatch at each location was unnecessary; the access pits were retained, but instead of openable covers, they were plated over and buried under the setts, the giveaway as to their location being that the setts immediately above each location were laid parallel with the slot instead of transversely. The conduit was also provided with drainage sumps every 120 feet, and these would have had access covers through which the cleaning "spade" could be inserted, and the detritus extracted. Access hatches for the extraction of collector ploughs were located at every section break, ie every half mile, and on the approach side of junction work.

A useful work on the subject of current collection methods in general, including the various conduit systems, is that by Messrs. Baddeley and Oakley entitled "Current Collection Methods for Tramway & Trolleybus Systems", published privately in 1975 by the authors but available (at least when I got my copy) via the Tramway & Light Railway Society, ISBN number 0 903479 04 4.

 

Jim

Thanks, Jim, for providing this before I return home this week.   What Geoff and Ted published was the basics.   When later we compiled the "LCC Tramways" books, we found what one expects in practice!!!   Yes, what was under the road did cause variations from basics!   On the subject of curves, one aspect I did not mention was the provision of water outlets on LCC 'bends' to lubucate the running rails.  LTE finally paying the Metropolitan Water Board's annual bill!!!   There were covers at the inlet points but just track drains to take the flow into the road drains.   Colin.

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