There is such a good item of correspondence at Pat Hammonds MREmag
it seems a shame to allow it to be lost. I for one want a permanent record kept that is easy to refer to in the future!
QUOTE (**Email of the Day**) I see quite a few readers have written in to confirm they can run modern ready-to-run successfully on today's Peco Streamline and reassure Bill Towers.
However, looking at the letters and also comments made elsewhere, there seems to be some confusion about the fineness of different types of 16.5mm gauge track. In particular there seems to be a belief that Streamline code 75 is 'finer' than Streamline code 100 and, by implication, that all code 100 track is the same.
If we are talking about the size of the gaps at the frog and between the check rails, which is what really determines 'fineness', this is not true.
The clearances used in current production Peco Streamline code 100 and Peco Streamline code 75 are exactly the same; I've checked this myself by measurement. The figures I have seen quoted are 1.39mm for the flangeway clearance on both sides and, as far as I can check with gauges, this is accurate. The only difference is the height of the rail. Therefore, there should be absolutely no difference between Streamline code 75 and Streamline code 100 as far as running is concerned - unless the flanges are so deep they strike the chairs or sleeper. I'm not aware of any current production ready-to-run where this is a problem - even a 20 year old Lima wagon seems to be able to cope with code 75. I'd be surprised if anything made since at least 1990 was unable to cope with code 75 rail.
Of course, Peco Streamline uses flat-bottom rail held in clips. SMP and C+L flexible track represents bullhead rail and chaired track, and the chairs are more prominent. The C+L chairs sit higher than SMP ones and there could be a problem with deeper flanges on these. However, in general, people using either of these do so in conjunction with hand-built points, so I doubt if they run much Lima with its original wheels. In general, I assume that when people say they use "code 75 track" they mean Peco Streamline code 75, but you can't be absolutely certain.
If it works on Streamline code 75, it should work just as well on Streamline code 100, and vice versa. There should be no difference unless the flanges are very deep indeed.
'Code 100' track is not all the same stuff. The Peco Setrack points I have are over a decade old and they have the same 1.39mm gap at the check rail, but at the frog the gap is 1.55mm - in this context a big difference. Peco Streamline code 100 is 1.39mm each side. As far as I'm aware, Setrack hasn't changed in recent years.
Setrack is significantly coarser than Streamline, whether code 100 or code 75. I can't answer for current production Hornby track; I suspect it matches Setrack and not Streamline.
So, when someone says they use "Peco code 100" it's quite difficult to work out exactly what is involved. Is it Setrack or Streamline, or a mixture? I would accept that Setrack may be too coarse for some of today's ready-to-run, but Streamline should be OK.
Just to make it even more complicated, sometime in the mid '80s, Peco tightened up the clearances on Streamline code 100. I suspect the original Streamline clearances of the '60s and '70s may have been like Setrack, but I've never measured any. So, if you are using 30 year old Streamline points you salvaged off an old layout, they may also be too coarse for today's stock (and Insulfrog points have a large lump of plastic at the frog and eventually this starts to wear so they become coarser).
Anthony New refers to Peco and Hornby points, so I suspect he may be using Setrack. He may also be using old Streamline points. That may explain his difficulties when other people seem to have few problems. So long as you are using only Streamline, and it's all less than 20 years old, you should have no real problems.
Graham Higgins refers to Roco-line and Fleischmann Profi. Someone very kindly sent me some Roco code 83 track. It has a flangeway of 1.1mm on one side and just on 1.25mm at the frog. This is a lot finer than Peco code 75 - about 0.5mm finer in total. I believe this is the NMRA track standard, so presumably Peco's new code83line is the same.
I'm sorry if this sounds all very complicated. This is basically because it is complicated.
If your head is still spinning, you'll probably have worked out why I feel describing track as "code 100" or "code 75" isn't very satisfactory, and why I feel rather uncomfortable when "code 75" is described as "finer" than "code 100"