Which chairs to use 2,3 or 4 bolt?

[clemf]

For my 2010 challenge I'm basing my layout at the south end of Copenhagen tunnel just North of Kings Cross late 50's. I've decided to try and build my own track from the C&L range. There seem to be several types of chair, 2,3 or 4 bolt. As I'm new to this which should I be using or does it depend on where the chair is, on a straight run, on points etc. Any advice would be very usefull. Its O gauge by the way.

[craigwelsh]

I'd recommend the Exactoscale range instead, its clearer what the types of chairs are meant to be for a start and they certainly prove better than C+L in 4mm.

 

GWR used two (its actually nuts on the GW one I think with the bolts underneath).

BR used 3

Midland used 4.

 

See the full range here:

http://www.exactoscale.co.uk/7mmtrack.html

 

Personally I think you'd be looking at S1 chairs, ie bog standard 3-bolt.

 

There is lots of information about point chairs in the instructions pages there but im afraid they only do the special point chair sprues in 4mm.

[R A Watson]

Presuming you are using 95Lbs Bull Head rail ( the standard rail in those days) and not flat bottom, which uses base plates not chairs, for your plain track, the normal chair of default will be the standard S1 chair, this is the three bolt version, the two bolt at this time was only widely used by the Western Region, who continued Great Western traditions till the bitter end, this application normally did not use the chair screws whose square head is visible on most track but a "Through bolt" the head of which is anchored below the sleeper by a cast plate with a nut visible on the threaded section poking through the chair. Four bolt chairs are normally "specials" used on switch and crossing works (points to the masses) which have a different footprint and dimensions and look to be square based, these are normally classified as L1 type or "Bridge Chairs". You may find these used in plain track on bridges and vaducts where the rail is carried on longditudinal bearers,these are in effect sleepers laid paralel to and below the rail hence the alternative name.

 

Hope this clarifies the situation.

 

Wally

[Trog]

The standard BR (Non Western) Bullhead chair was the AS1, with in the early part of its existance AS1J chairs at the joints. The AS1 is just a update of the original S1 chair and will look no different in O or OO. The AS1J is an AS1 with a larger base to spread the extra impact loads experienced at the joints, it would usually be used on a 12" x 5" sleeper instead of the standard 10" x 5".

 

As stated most slide and crossing chairs have four chairscrews, although you may find the two inside screws at the toe are not fitted.

 

On Longitudinal timbers and at the heels of switches L1 chairs are used, these are an AS1 shortened in length until it is square in plan with a screw at each corner. On longitudinal timbers that are narrower than normal and on slips you will find the even smaller M1 chairs, these are again square, and are basically a set of chair jaws, with a screw sqeezed in each corner.

 

 

http://www.rmweb.co.uk/community/index.php?app=gallery&module=images&section=viewimage&img=8983 Photo of S1 Chair.

 

 

[martin_wynne]

(its actually nuts on the GW one I think with the bolts underneath).

Hi Craig,

 

But only for plain track. For GWR and BR(W) pointwork, the chairs are screwed or bolted down from above.

 

Personally I think you'd be looking at S1 chairs, ie bog standard 3-bolt.

Bear in mind that these are actually chair screws. Calling them "3-bolt", "4-bolt", etc., is misleading -- they are not bolts. Only the GWR and BR(W) are correctly described as "2-bolt".

 

regards,

 

Martin.

[Trog]

The CS1 and CS2 bullhead chairs for type E concrete sleepers, and the Pan9 flatbottom baseplate designed to replace them also use two bolts through the sleeper with the nuts above the chair/baseplate.

 

 

 

http://www.rmweb.co.uk/community/uploads/1259865814/gallery_7181_438_30054.jpg

 

Picture of a Pan9, the nuts on a Western Region AS1 equivilent and CS1 or CS2 bullhead chair would look similar.

[Kenton]

Having spent the last 3 evenings (and many more to come) squinting at Peco sleepers (4mm) .. it has come to my attention that they have 4 bolts But I must add that I require a magnifying glass to see them and am wondering if it really matters to the normal eye in 4mm. (Yes I know the OP clearly stated for O gauge)

Interesting all the same, I had not even realised there were differences.

[craigwelsh]

Having spent the last 3 evenings (and many more to come) squinting at Peco sleepers (4mm) .. it has come to my attention that they have 4 bolts But I must add that I require a magnifying glass to see them and am wondering if it really matters to the normal eye in 4mm. (Yes I know the OP clearly stated for O gauge)

Yes but they also feature flat bottom rail making them largely irrelevant to the sorts of designs we were mentioning.

 

The chairs on most finescale track systems are a lot bigger so you don't have to squint so much.. Personally I do find you can tell the difference and if you are going to the trouble of building from components its worth choosing the right ones.

 

Martin what do the chair screws screw into? Straight into the sleeper or is there an insert/baseplate? I'd always thought of them as just the opposite to GW.

 

There is a photo of a broken GW 2-bolt chair here http://www.rmweb.co.uk/community/index.php?app=gallery&module=images&section=viewimage&img=8940 I hadn't looked closely at the pointwork yet to realise they were bolted from above so thanks for that.

[clemf]

Thanks for the replies. I should have known it wouldn't be as easy as I'd first thought.

[LNERGE]

I've been looking at pictures of the line between Gasworks and Copenhagen tunnels. I'd say there wasn't that much bullhead in that area. It looks like 109lb flatbottom.

 

Edit.. After a brief rummage through my piles of paperwork i've found a drawing for a 1378.5 feet radius right hand D switch with a 1 in 12 common crossing. This was installed at Arlesey in 1964 and i note that the stock rails are 110lb flat bottom and the check rails are 98lb flat bottom.

[martin_wynne]

Martin what do the chair screws screw into? Straight into the sleeper or is there an insert/baseplate? I'd always thought of them as just the opposite to GW.

Hi Craig,

 

Pic of chair screw: http://rpm-railpics.fotopic.net/p34892319.html

 

From this excellent site of p.w. details: http://rpm-railpics.fotopic.net/c1121991.html

 

For new timbers the screw is direct into the timber, which is bored with a pilot hole to suit. In worn holes a heli-coil or rawlplug type insert is sometimes used if the screw won't pull tight. A tapered ferrule is used in the fixing hole in the chair casting to prevent lateral movement.

 

regards,

 

Martin.

[IC126]

I'd recommend the Exactoscale range instead

 

I'd agree with this - I think that the 7mm Exactoscale chairs are better than C&L, mainly due to the crisper representation of the hexagonal wooden key.

 

 

3 bolt Exactoscale on the left, 4 bolt C&L on the right.

 

Going back to the OP's question: 2, 3, or 4 bolt chairs?

 

I use the BR standard 3 bolt type for main lines and the 4 bolt type to represent reused pre-group equipment for sidings.

 

The Exactoscale 3 bolt type has (as previously stated) not bolts, but square headed chair screws (quite nicely represented.) Older types (at least in Scotland) have a round headed pin, hammered into the sleepers.

 

I've rarely seen two bolt chairs on the prototype, although I know they were used - I have seen ex LNER concrete sleepers with two bolt chairs which were recovered from the West highland line. The preserved Caledonian Railway (Brechin) had a supply of these which they considered using on a particularly wet section of line. They were quite deep and monstrously heavy though.

[Bernard Lamb]

Thanks for the replies. I should have known it wouldn't be as easy as I'd first thought.

 

 

Try building some NER track using 3 bolt chairs but the other way around if you want some real fun. AFAIK they are not available commercially. 'Tis a very complex subject.

Bernard

[craigwelsh]

Try building some NER track using 3 bolt chairs but the other way around if you want some real fun. AFAIK they are not available commercially. 'Tis a very complex subject.

Bernard

Is that inside chaired or just the holes swapped over? I know Exactoscale sell a 3-screw in 4mm with the holes being on opposite sides to an S1/AS1, supposed to be LSWR I think.

 

One of the LMS companies used inside chairs at some point, possibly the Midland?

 

Thanks for the picture of that screw Martin, i'd not found that site before and there are some useful shots.

[clemf]

Just got to work out what I need to order now, then hours of fun trying to make it all up.

[Jaggzuk]

Look out for the book "British Railway Track - Design, Construction and Maintenance" by the Permanent Way Institution. Although a bit technical, it is a useful resource.

 

I came across mine which is a 5th ed in a second hand book shop for ??12. You can also buy the latest version from the PWI at http://www.permanentwayinstitution.com/PWI%20Order%20Form%201-2006.doc, but it is a bit more pricey.

 

Paul

 

(Sorry about the weblink, the java script to inset it is not currently working)

[Bernard Lamb]

Is that inside chaired or just the holes swapped over? I know Exactoscale sell a 3-screw in 4mm with the holes being on opposite sides to an S1/AS1, supposed to be LSWR I think.

 

 

 

 

Yes. Inside keyed. It was probable one of the constituent companies of the NER that used them originally. Middleton in Teesdale branch had them certainly into the BR period in some of the sidings.

Bernard

[Penlan]

Look out for the book "British Railway Track - Design, Construction and Maintenance" by the Permanent Way Institution. Although a bit technical, it is a useful resource...... Paul

 

Another 'interesting' book is the Edgar Allen Trackwork Catalogue, hard back, 200+ pages, plenty of diagrams, tables, loads of photo's etc. It does cover proper Railways in the UK and the World as well as narrow gauge, Tram track and all sorts of industrial schemes. My copy is dated March 1949 - there were a 1,000 copies. I paid 15 GBP's for my copy in a Penzance book shop.

 

Penlan

[Rambler]

If you are modelling LNER trackwork then you should have a copy of the following NERA publication:

 

STANDARD RAILWAY EQUIPMENT - PERMANENT WAY, 1926

A 94 page facsimile reproduction of the 1926 book of permanent way track standards using 95lb B.S. rail. This book of scale detailed plans and drawings show full timbering and chair details for turnouts, crossings, switches and slips as well as drawings of individual components which made the point-work of the period. Details of check-rails, stretcher-bars, chairing for Waybeams are also included.

Price at NERA Meetings: ??5.95, Price by Post: ??7.50

 

AFAIK this standard was used for (LNER) bullhead track work until it was superseded by flatbottom. I also seem to remember being told that this one of the main inputs for the Exactoscale range of track, which is quite likely given that Andrew Jukes (of Exactoscale) is an LNER modeller.

 

A small word of warning - real trackwork is a lot longer (due to the use of larger radii) than most model trackwork.

[Trog]

Is that inside chaired or just the holes swapped over? I know Exactoscale sell a 3-screw in 4mm with the holes being on opposite sides to an S1/AS1, supposed to be LSWR I think.

 

One of the LMS companies used inside chairs at some point, possibly the Midland?

 

Thanks for the picture of that screw Martin, i'd not found that site before and there are some useful shots.

 

 

 

I have read that the Midland used inside keyed chairs, although I have only ever found the outside keyed type in the wild.

 

The problem with inside keyed track I am told is that as trains passed they press the rails away from the keys, allowing them to work out over time.

[buffalo]

I have read that the Midland used inside keyed chairs, although I have only ever found the outside keyed type in the wild...

The GWR used inside keyed chairs from around the 1860s when they needed to use cross sleepering. There were several patterns of chair to go with different weights of rail, but all, I think, were two bolt forms. I believe the outside key type started to appear in the the 1880s although the later inside key types can often be spotted on photos of branch lines and sidings up to about 1920. No doubt some even remained thereafter.

 

Nick

[Trog]

I think there were some inside key GWR chairs in some S&C at Chinnor cement works on the Wattlington branch at least into the 1980's.