Which gauges for track construction?

[Bigfish]

I’m a bit confused about which gauges I need in order to start plain track & turnout construction. I’d very much appreciate your suggestions as to which ones I need (from the Society stores), and how many of each? As ever, thanks so much for your patience!

[craig_whilding]

I'd suggest reading through the responses to Knuckles' recent threads as he was asking for similar help and got the recommendations on what to buy then.

[Bigfish]

Hi Craig, I'll do that and thanks for pointing me to it. Thanks also for your response on "reading recommendations"!

Cheers

Alan

[Bigfish]

Well looking at my post again I think I was being a bit idle just expecting the answer! So I read up the relevant bit of Iain Rice’s “An approach to building finescale track in 4mm” – which I appreciate is out of date in some respects (eg I’m planning to make track using glued plastic chairs to ply sleepers, not rivets), but nevertheless seems OK in this area. His list suggests the following, which I’ve attempted to match to the Society stores list. The quantities are his “bare minimum” numbers with “nice to have" in []:

(a) 190 Track gauge, triangular, for automatic gauge widening, or DD-190 Track gauge, triangular, for automatic gauge widening new type, DD Wheelwrights (2 [3] off)

- I’m not sure which to get, DD-190 being a post-Rice addition?

(b) 193 Checkrail gauge (1 [2] off) - this is currently out of stock, so I’m a bit stuffed unless the “boxed set” (see below) is available with one in it.

(c) 192 Flangeway gauge (1 [1] off)

Item 196 is the boxed set of 4 Gauges (roller, Type 'A', checkrail & flangeway). I’m not sure what a “type A” is.

If I get one boxed set plus 3 triangular 190s or DD-190s, should that do the trick?

[grovenor-2685]

Well looking at my post again I think I was being a bit idle just expecting the answer! So I read up the relevant bit of Iain Rice’s “An approach to building finescale track in 4mm” – which I appreciate is out of date in some respects (eg I’m planning to make track using glued plastic chairs to ply sleepers, not rivets), but nevertheless seems OK in this area. His list suggests the following, which I’ve attempted to match to the Society stores list. The quantities are his “bare minimum” numbers with “nice to have" in []:

(a) 190 Track gauge, triangular, for automatic gauge widening, or DD-190 Track gauge, triangular, for automatic gauge widening new type, DD Wheelwrights (2 [3] off)

- I’m not sure which to get, DD-190 being a post-Rice addition?

I managed for years and built lots of track with just the one 190, I did eventually get a second one when it came up on the bring and buy, its useful but not essential. The DD (Dave Doe) version is indeed much newer, IMHO it is less useful for building track as it does not hold the rail in place as well as the 190, but it has the advantage that it sits on the railhead only and is good for checking chaired track. (With the 190 you need to keep the rail clips between the chairs. Where you are now I would suggest one of each.

(b) 193 Checkrail gauge (1 [2] off) - this is currently out of stock, so I’m a bit stuffed unless the “boxed set” (see below) is available with one in it.

I believe the boxed set does include one. Its good practice to use these but only really essential where the curves through the crossing are curved enough for the gauge widening to be significant. Otherwise the check rail flangeway should equal the crossing flangeway and you can set check rails with a flangeway gauge.

(c) 192 Flangeway gauge (1 [1] off)

in a similar way to the triangular gauge there is also a DD version of this. The original is a rectangular strip and needed the align the vees with the wing rails properly, the DD version is a round washer and OK for checking the gaps after build but really has no advantage over the original. Best to get the original version.

Item 196 is the boxed set of 4 Gauges (roller, Type 'A', checkrail & flangeway). I’m not sure what a “type A” is.

The roller gauge is useful occasionally, but really only for straight track so not a must have.

If I get one boxed set plus 3 triangular 190s or DD-190s, should that do the trick?

See above, definately get one 190, and i would suggest a DD-190 as well, a third is just a luxury, wait till you have used them a bit and know which you prefer and whether you need more than the 2 for anything.
Regards
Keith

[Bigfish]

Keith, that's such a help! Right, let's get that order in to the Stores!

Regards

Alan

[craig_whilding]

Just to say I concur with Keith and I think its pretty much what Knuckles ended up buying after his thread too.

I certainly agree with him the older 3-point and flangeway gauge are better. Make sure you don't end up with an S4 flangeway gauge either, its narrower than P4..

Anyone up for writing a guide to the use of all these gauges for the site now we've had two new members asking what to buy for what? (no don't point back at me )

[Alan Turner]

The gauge that is a must-have is the check-gauge that must always be used to set the checkrail.

Alan

[craig_whilding]

The gauge that is a must-have is the check-gauge that must always be used to set the checkrail.

Alan

Doesn't work so well with plastic check rail chairs though.. As Keith said, its not normally giving you much in most situations unless you really go for a lot of flowing crossings.

[Bigfish]

Many thanks to all of you for your help and patience! I ordered one 190 and one DD190 (ie an old and a new triangular gauge), and a boxed set which hopefully has all the others.

Regarding "Anyone up for writing a guide to the use of all these gauges for the site now we've had two new members asking what to buy for what?" I'd obviously support such a brilliant idea! I can contribute at least a selection of the dumb questions, if someone knowledgeable will fill in the answers! I wondered for example in relation to "track building" if there was room for some sort of supplement or commentary on "developments since Mr Rice's book", particularly in relation to how Templot can be best used, and the plastic chair revolution. What do you need to buy from Stores/C&L/Exactoscale? Oh, and maybe, wiring them for DCC..... Or, I'd be happy to submit my own answers to my dumb questions, providing someone else corrects them!

Thanks again

Alan

[grovenor-2685]

There are already detailed articles on use of these gauges on this site or linked from it.
ie in the Protofour Manual which gives considerable detail.
And the Scalefour Digest track section which covers most of these issues.
Templot has an entire website devoted to it going into everything in great detail.
Plastic chairs are covered in some of the S4 Digests mentioned above and there are detailed instructions on using their parts available from the P4 Track Company, go to http://www.p4track.co.uk/ and click on the "instructions2 button in the header, then choose your download.

On top of all this there are tutorials on websites, another sample here, books such as the Iain Rice one and IIRC Norman Solomon did a video.

there is also a beginners article in here.

On top of all this you can ask questions on here whenever the mood takes you.

I don't really see a need for any of us to sit down writing all this again in another document when the info is already available either on this site or linked from it.
Best
Keith

[LesGros]

I agree with Keith, and the guidance he points out should answer most of the early questions for the beginner.
However. the content of beginners' recent posts does suggest that a short intro guide to newcomers, which points out the way to get started, could be a useful addition to the new-member's pack. Perhaps including a page of FAQ could be helpful too.

regards to all

[doktorstamp]

LesG's comments on providing info to newcomers struck a chord with me. I have no doubt all the information needed is in the archival section, but the indexing when I last looked left a little to be desired.

A 'sticky' for newcomers would I feel be most welcome, such that with one click the information would be available.

It is neither desirable, nor practical to place everything there, but in particular track construction and re-wheeling, and maybe brass kit construction could be dealt with in this way. However from experience of other forums where 'stickys' are provided, members should refrain from replying with see here etc. as this is oftimes off-putting for newcomers. I realise typing, " The information you seek can be found here" takes a little longer, it is however far better received by the newcomer.

Just my 2 cents

kind regards

Nigel

[Bigfish]

Thanks for those further thoughts, and thanks Keith for your trouble in assembling those various links. For example, although I've looked at the Exactoscale website on numerous occasions, I hadn't found the detailed "instruction" sheets, which actually answer most of my questions about chairing. I think as a newbie all I need, mostly, is that sort of guidance, rather than more specially written stuff, especially since there is a limit to the amount of time and energy anyone can put into doing this. I am sure everything I need is out there, it's just a question of finding it.

Cheers, Alan

[Alan Turner]

The gauge that is a must-have is the check-gauge that must always be used to set the checkrail.

Alan

Doesn't work so well with plastic check rail chairs though..

If you use those you can't have any gauge widening because it is an absolute must that the check rail at the crossing must be set with a check gauge.

regards

Alan

[LesGros]

Craig wrote:

...Doesn't work so well with plastic check rail chairs though..

If I understood a recent discussion with Len (Exactoscale) correctly, the Exacto' check rail chairs are NOT intended for use on crossing-checkrails, but are designed for use for check rails on bridges and low radius curves, per prototype.

[John Palmer]

If Exactoscale check chairs are unsuitable for mounting the check rails of crossings, how do you go about this when using functional chairs for track construction? Is there no alternative to ply and rivet construction, if only to mount the check rails?

[grovenor-2685]

The Exactoscale point kits use check rail chairs to hold the check rails as does the prototype. This is fine so long as you don't need gauge widening at the crossing. Which you should not unless using turnouts smaller than 1:6 or curved turnouts with tight radii.
The following is the quote from the P4 track co instructions, link to complete documents given above.
Keith

Remember that setting the track gauge (TG) will, with a fixed check rail
flangeway, set the Check Gauge (CG) dimension too.
Setting TG at the crossing to 18.83mm will give a CG that complies with the published P4 standards.
Setting TG to +0.1mm will give a CG of 18.25mm.
If you wish to use S4 (exact scale) dimensions, it is best to replace the 0.68mm flangeway check chairs
with 0.58mm ones (when available).

[allanferguson]

Craig wrote:

...Doesn't work so well with plastic check rail chairs though..

If I understood a recent discussion with Len (Exactoscale) correctly, the Exacto' check rail chairs are NOT intended for use on crossing-checkrails, but are designed for use for check rails on bridges and low radius curves, per prototype.

I hadn't realised that, and I've laid several turnouts using the 0.68mm check chairs, which have given no trouble. The radius at the checkrails is 2200mm. One thing which did give me some grief was my failure to realise the the sprue includes chairs for the flare, which are not immediately distinguishable. Alan is quite right, of course, that the check rail should be set from the opposite running rail, but this is true whatever the radius. However the prototype uses special chairs, a la Exactoscale, which presumably are of fixed size.

Incidentally, to go back to the original posting, I have aquired four or five triangular gauges over the years, and find these very useful because they hold the rail in position while I fix it.

[LesGros]

Keith wrote:

...The Exactoscale point kits use check rail chairs to hold the check rails as does the prototype. This is fine so long as you don't need gauge widening at the crossing. Which you should not unless using turnouts smaller than 1:6 or curved turnouts with tight radii. ...

Thanks Keith, I stand corrected.

[John Palmer]

A quick test in Templot indicates that in 4mm scale an REA B6 has a centreline radius of 1153mm on the diverging road (main road is straight). This is equivalent to 4.36 chains and thus well into gauge widening country for track other than pointwork. For turnouts in which both roads have the same flexure my current design avoids anything less than a crossing angle that is less than 1:10, but in most cases the minimum radius is nonetheless in the region of 6 scale chains, and in a couple of cases goes down to about 5.5 chains. I gather different rules about gauge widening may apply to pointwork, although I haven't seen any details of such differences. Does this suggest that accurate check rail construction using functional chairs still poses a problem?

[Russ Elliott]

The prototype, where all flangeways are set to 1.75", has no recognition of the concept of CG. The P4 official recommendation is that gauge widening should not be applied to any sections of pointwork where CG, CF or BC dimensions are specified, hence for a straight crossing, using a check gauge will have the same effect as using a crossing flangeway gauge at the check rail. Although a turnout centreline radius figure is not carried through the vee area of a B6 for example, sharp radii turnouts can be problematic in setting the checkrail on a curved road if it desired to use standard 0.68mm check chairs. Our triangular gauges provide only half the amount of gauge widening the prototype might use for a particular radius, so over the vee area of a turnout, the amount of gauge widening applied by the use of the triangular gauge will therefore be small. The difference between the theoretical CG setting by using standard 0.68mm check chairs and the idealised CG setting will be smaller still, and ultimately it depends on the inherent accuracy of a check gauge, which is unknown since the accuracy of those artefacts is impossible to validate.

The specified CGmin and CGmax values are predicated on assumptions of BB setting. Where BBs are set fractionally wider than the upper P4 bound of 17.75mm, the use of standard 0.68mm check chairs is unlikely to result in any problem except in the most extreme circumstances, and for such wheelsets 0.68mm checks on divergent roads can be seen as a good compromise setting between the prototype 0.58mm setting and a circa 0.75mm setting as might be given by the use of a check gauge.

It does mean that you can't run an 8-coupled through a B6 at 50smph, but you didn't want to do that anyway, did you?

[John Palmer]

Thank you, Russ, that is quite reassuring. I had not appreciated that CG was an unrecognised concept on the prototype.

I note that Exactoscale also offer check chairs with .8mm flangeway, as well as those with .68mm. Can someone please explain the intended purpose of these? I can't find any explanatory material on their use, and I'm struggling to understand how the techniques applicable to the ply and rivet construction that are familiar to me need to be changed when using functional chairs.

50 mph through a B6 looks like a recipe for another Goswick! Normal speeds for my proposed model will be substantially less than this, but some 20' WB six wheelers will have to pick their way through the pointwork, which is planned to reflect North British practice.

[grovenor-2685]

I think the 0.8mm check chairs are intended for continuous checking on sharp curves where you do need gauge widening.
Of course they would also be useful if you want to widen the gauge through a crossing, and are mentioned for this latter purpose in the point kit instructions.
Regards
Keith

[Russ Elliott]

John - 0.8mm check chairs provide a useful function in two cases:

- straight-ish or gently curved track, e.g. a level crossing or an inset goods yard road, where we neither need nor want any actual wheel checking to take place, i.e. in such applications the check rail is essentially cosmetic;

- sharply curved track where GW in the region of 0.2mm is being applied (if considered or found to be necessary), where the 0.8mm check will be in about the same place as would be given by the use of a check gauge.

In soldered ply and rivet construction, use of a check gauge will position the check rail with some precision, whereas with set-width plastic check chairs only two settings of the check rail, i.e. 0.68mm and 0.8mm, plus 0.58mm (when these become available) for the exact-scale fans.

Interestingly, in double-checking applications on flat diamonds, where the recommended P4 settings are problematic (see condition 3 of the Technical derivation of P4 track and wheel standards), Exactoscale has found it necessary to close up the CF setting slightly tighter than the 0.65mm value for CFmin

In balancing the need to avoid undue (hard) checking against the possibility of a wheelset taking the wrong route at a vee or a K crossing, the use of a BB slightly in excess of the 17.75mm BBmax value will probably be found to be beneficial, since the likelihood of the latter increases only as the value of BBmax approaches the value of CGmin