Life started with a ‘Christmas train’....

[Mountain]

The main thing to remember when mixing sectional track and flexible track with the Peco range is that the railheights are the same. The railheights are shown as code 100 or code 75 etc. Hornby track and Peco sectional track use the higher profile code 100, so to match that railheight, use the Peco streamline code 100 flexible track. (The points are not flexible. Only the yard lengths of straight track which one can use as is or curve them as desired).
Code 75 can be mated up to code 100, but one needs either special converter rails, or special railjoiers, or one can pack underneath the code 75 rail and simply solder them to the code 100 track. It is probably best though to stick to code 100 if one is to mix flexible and sectional track, but there is no set rule in this except to say if you do mix them, try to have a whole area of code 75 and another whole area of code 100 rather then have a single piece of code 75 on an otherwize code 100 layout or vice versa.
Also code 100 will run deep wheel flanges, while code 75 can only be used with finer scale more modern wheels. Why sticking to code 100 is better until one gets to know what runs with what, as code 100 is the "Jack of all trades" when it comes to 00 gauge and H0 gauge track.

Something I will say for a visual idea is that with the more modern railways in real life, the rail heights have increased significently because the weights of goods trains has increased with much heavier and larger wagons being carried. So if one has a main line of higher profile code 100 track, one can use code 75 in sidings as in real life the older lower profile track is often seen in sidings.
However, if you are modelling in steam days then this idea will not work, as it is only really in the last 40 years that the real railways have used higher profile rails on their main line track, so sticking to code 100 (Unless you want to do finer scale modelling) is probably the best idea.

Not to confuse you too much. Peco Streamline points are usually available in live frog (Electrofrog) or dead frog (Insulfrog) forms. Hornby points are all dead frog points.
The advantage of dead frog points is that they are simpler to use. Just join them up and as long as the track power is fed through the single track end of the point, all will be good.
Live frog points usually need (Depending on circumstances) extra wiring to switch the frog polarity, but they do have the advantage that if one runs a locomotive at very slow speed over them, they are less likely to stall. Mind you, modern Peco dead frog points only have a small area which is dead so it is not often ones trains will stall. The usual recommendation for a beginner who just wants to get ones trains to run is to use dead frog points and there is nothing wrong with using them. Most of mine were dead frog when I was into 00 gauge, but if one wants the very best slow speed running and one does not mind extra wiring and a switch etc, then live frog points are for you. (Many modellers find a way to mount the frog switch in such a way that when the point changes, it also switches the switch and there are ways of doing this).

I only mention electrofrog and insulfrog (Live or dead frog) so if you come across it, you will know what it is. (Even if in theory).

[Flashbang]

The major difference between Peco Streamline and Setrack in OO are:-
The natural spacing of parallel tracks. Setrack/Hornby automatically spaces the parallel tracks at 67mm centres, but Streamline reduces this to 50mm centres.
Next Streamline has no rail joiners factory fitted where as Setrack and Hornby have a metal joiners on the track/point section rail ends- One on each end. You need to obtain metal joiners Peco SL-10 or Insulated joiners Peco SL-11 when using Code 100 Streamline track.
All Streamline points are to a much larger footprint than Setrack / Hornby, so are therefore not a direct drop in replacement for any Hornby or Setrack point.
The smallest curve radius on a Streamline code 100 point is currently 610mm.
As stated, there are no sectional pieces of track sold in Streamline.
Code 100 Streamline will connect to Peco and Hornby current track ranges, as they all use Code 100 rail profile.
You have to remove the first sleepers rail chairs on Streamline flexible track to allow the rail joiner to slide onto the rail - Streamline points have the sleepers rail fixing pre removed.

[Tigcraft]

Hell fire I’ve a a lot to swallow after reading the last four posts!
@mountain, I’m going to do a dual track loops which I’m very happy about. Don’t think I’d be happy if it was just ‘there-stop-back’. I might have to be sensible and run slower speeds for my Scotsman but slow is far better than leaving it as a boxed up present. Your knowledge is superb. It’s quite a fascinating story about the 100mph trials from so early on. As for ‘frogs’? There’s some strange names out there that create more laughter that clear info.

@end2end I’ve not bought any extra track as yet but the radius’s are interesting to know.
@flashbang your info has been logged too.

[Tigcraft]

Looks like the grand kid beat me to it!! So this is one of three sections to my ‘L’, Might try a figure of eight crossover on this section.

I’m shocked how noisy that plastic thing on there makes as it’s very quiet on typical carpet. On the two bits you see here it runs around 2200mm long by around 1000mm at the widest

[Tigcraft]

Rest of the pics. This is just dropped in and raw cut to see if the layout left me with acceptable remaining room space.

I’ve to make a suitable sectional framework to Connect the lot together. This platform will most likely be 600mm above floor level for general room access.
The upper area I’ve marked out leaving 67mm between centres based on Hornby example.