How are the radii of points known

Hi All            I am confused:???: I used to get a piece of string and two points (one being a pencil) to measure a radius! Simple. But I do not get the "Frog number" thing, which is the largest radius down to the smallest radius? And are the smallest radius points only suitable for "Puzzle Yards" with short wheelbase loco's? Do I ask for a Number or a Large, Medium or Small?? all the best  Kevin

It depends if you're buying Peco "Streamline" points or "Set Track" points Kevin.

"Streamline" are designed with flexitrack in mind (but they will also connect to set track).  It's only my opinion, but they look much better than set track - they "flow" - hence the name "Streamline".

Streamline are sold as large, medium or small radius.  Set Track points are sold as 1st, 2nd & 3rd radius.  They don't tally exactly with the Streamline version but it's the same principle.

If you are building your own points, then they go by "numbers" - a No 5 point, for example.  This is how the "real world" operates …………..

All short wheelbase locos will negotiate "small" or "1st radius" points but my advice would be not to come below 2nd radius in the set track range.  The tighter the radius, the shorter the wheelbase needs to be.  Most longer wheelbase locos are not designed to go around anything tighter than 2nd radius.

Thank you Petermac      For your advice. How silly I am? I meant to say "Peco code 75 Streamline", My Plans are dragging on and I keep changing them. Sometimes I think that "N" gauge would have been better? but, "N" gauge in my hands would not work too well.                                                                        all the best  Kevin
                                               

Just had a look at Peco web pages, set track points in N gauge are only done in radius 1, although the streamline small radius is almost set track R3, 1/4" difference.

Hi Kevin,
Frog numbers - the lower the number the tighter the radius. A #5 diverges 1 foot in 5, a #9 1 foot in 9. RTR turnouts bears little resemblance to the real thing. Tight radii become a problem with long wheel-base engines - that's why models have lots of lateral movement. In real life eight coupled engines would have at least one pair of wheels without flanges or would have jointed rods with lateral movement to get around tight curves in yards. Mainline curves are around 50-70 feet (or greater) radius in OO, very few of us have that short of space available. 
Nigel

Hi Nigel                 Thank you for the info. That is another piece of knowledge for my "Book of Track Design". all the best Kevin

Hi Kevin,

There are some strict definitions regarding the calculation of the radius of a turnout. Plus it gets even more complicated when the different types of switches used in the UK come into play (essentially a short or long turnout). Unless you build your own track not anything to worry about. Use what works for the layout and the engines.

Plenty of resources online (NMRA for example), if you need to calculate the radius/frog# download the Peco templates and proceed from there. C+L Finescale has some useful information. Interestingly Peco sell their code 83 (for North America) as number 6, Number 8, etc. Calculations for a wye get interesting (#5 wye =#10), as do slips.

Use #6-8 for mainline (real-life #10-20), #4-8 in the yard (I wouldn't use anything less than a #6). Bigger the frog number, the longer the turnout.

Nigel

  

Hi Nigel.     Thank you again this hobby gets more complicated by the minute! But I will be keeping to Peco code75 ready made points and track,
Kits are okay when they stand by the line side.( signal boxes etc),but even then I came unstuck? recently when I picked up a bug or why on my computer. when I downloaded a free ."low relief house kit" or so it seems because I had to get that put right.      Kevin

Hi Kevin,

Knowing you are going to use Peco Code 75 track, this link may be helpful to you :

http://www.peco-uk.com/prodtype.asp?CAT_ID=3327 It shows all the whole range of Peco code 75 track available.

For track templates (printable download) useful for planning your track design, see here :

http://www.peco-uk.com/page.asp?id=tempc75 This should help to no end. :thumbs

Cheers, Gary.

Hi Gary.  Thank you for your reply, I read about code 100 being a bit oversize??  and all my locomotives  and rolling stock are recent (Chinese) models. This is a very good forum, and I have already been sent the Peco download, thanks all the same but don't forget me all messages will be  appreciated and answered asap (fair dinkum) Kevin

Hi Kevin,

Gary's post prompted me to have a look at the Peco range. I see Peco now do their 3-way turnout in code 75. If you are planning on a fiddle yard or storage sidings get one (or 2), it's a real-estate saver, especially if you are short on space (who isn't in this hobby). If you don't have silly pick-up arrangements on the engines (2 wheels one side, 2 wheels the other - Lima GWR diesel railcar for example) go with insulfrogs in the fiddle yard as well. Less messing around with wiring if you ever go DCC as you don't need to switch polarity.

Rather than design the track just print the Peco templates and use them pinned or glued to the baseboard to see how it all fits (make sure the printer prints at 100%). Peco have a neat plastic track gauge that makes sure the distance between tracks is correct. Your hobby shop will have one.

Nigel

Hi Nigel               Yes that seems like a space saver alright, I have already purchased a D C C controller, I only have an 08 shunter at the moment but it has been fitted with sound. Living in a modest house, my baseboard only measures eleven feet by two feet, with a right angled "shunting puzzle board" measuring three feet eight by two feet, my next job is to prepare the board surfaces (Varnish maybe??) before I can lay any track, and if I realise the six (or four} track low level viaduct/ embankment, then that will need to be built and wires made ready for connection first. Will the dream become reality?    all the best  Kevin

Hi Kevin,

Quick question - what is the board surface? Varnish (solvent or water-based) will give a nice, smooth surface to which water-based glue (PVA) will not stick. Use some unvarnished cork (1/8") and contact adhesive or the black dense foam track underlay to lay the track on. It'll keep the noise down and the glue will stick to it. Buy cork in rolls, tiles will have too many joints that will lift with time. If you want to paint before hand use cheap matt emulsion. Varnish the frame by all means, it keeps warping down, although the emulsion works just as well. I buy returned cans (the "oops" brand) from the local DIY center that are approximately the color required.

Nigel

Hi Nigel             The more I read about Plywood/Warping and the best way to ballast track the more questions pop up:???:, some modellers say Paint, others say Varnish, I even read about using "Fence Paint", on this forum. If I understood it correct? one member stuck the track down direct on the baseboard ( because cork does not deaden the sound once it is stuck down) and then did the ballast, let it dry overnight, and then using the cheapest Varnish? covered the rest of the board. Have I read your advice correctly?? Varnish isn't any good because nothing sticks to it, it is best to use cheap Paint.                all the best             Kevin

Hi Kevin,

Track laying and ballast, probably the one area of the hobby with more old-wives tales, folklore and black arts than the rest of it put together. I'm on my 5th home layout layout and have worked on 2 club layouts, so no expert, but my observations over the years are as follows. Hope it helps.

Cork is a cellular material, irrespective of whether it's glued or not it provides an acoustic barrier. Which is important, as that baseboard is one big acoustic amplifier. It also provides a convenient shoulder for the ballast. Not necessary in a yard or branch lines especially if using Peco track. The closed cell foam underlay (Woodland Scenics or the like) does the same. I use 24" wide 1/8" or 1/4" thick cork rolls, as cork tiles give too many junctions, and water-based contact adhesive. It also allows a nice transition between the main line and sidings, which are normally 6"-12" lower to stock from running onto the main line.

Baseboard frames need sealing (paint or varnish) to protect against changes in humidity that can result in warping. This really applies to dimensional timber, this is less so for good quality plywood. Dimensional timber (and even plywood) can have a high moisture content from improper seasoning or kiln treatment, especially the imports. Caveat emptor. Sealing does not protect against temperature-induced dimensional changes. I stopped using dimensional timber a long time ago, all my baseboards are made from ply - sides, internal braces and top. Paradoxically, finger jointed dimensional lumber products are more stable than regular lumber.

I would recommend sealing the top after the track underlay is in place. I use low VOC emulsion paint (green and brown), as it gives a surface to which PVA will stick. I have on occasions painted the cork where the track goes a color which will match the ballast. There is no reason to paint the cork where the track will go, after all it will be ballasted and sealed with glue.

HD styrene foam has other issue not related to humidity, but that's another story.

Nigel

Hi Kevin,

Just remembered you will be using Peco code 75 (which is really HO track). The sleeper spacing and sleeper width on Peco track is more appropriate for 3.5mm scale (HO), not 4mm scale (OO). It's also FB rail with plates and spikes, whereas in the UK up until well into BR days it was BH rail with chairs (2, 3 or 4 bolts).

One way to get a more prototypical look is to cut out the continuous and discontinuous web between the sleepers and increase the spacing slightly using a jig made from some styrene sheet off-cuts. If you want to be pernickety, decrease the spacing at rail junctions (every 44-60 feet or so, check because different companies had different standards). The pictures I showed were C+L Finescale OO track, which has thin sleepers of prototypical width (and hence requires less ballast) and more prototypical spleeper spacing. For the GWR the spacing for 44' 6" panels, 18 sleepers per panel, was 2' 6 1/2" (sleeper center to sleeper center), the 2 sleepers next to the joint had spacing of 2' 1 7/8", and the spacing over the joint was  2' 1 1/32". Templot software has lots of these details.

Peco track is also easier to ballast if the spacing between the sleepers is increased by a mm or so, and removing that webbing allows daylight to show under the track between the sleepers.

Practice on that piece of track until it looks right to you. If you can get some old Graham Farish OO track ("Formoway") that has more prototypical sleeper width and spacing. Chalk and cheese when next to Peco track.

Nigel