Editing 4 mm scale (section)

===P4===
[[Protofour|P4]], otherwise known as [[Protofour]], or "18.83", is a close to exact 4&nbsp;mm:1&nbsp;ft replica of real-life track and wheel dimensions.<ref>{{Cite web |last=Elliott |first=Russ |title=Scalefour Digest 1.2 'P4 Track and Wheel Standards' |url=http://www.clag.org.uk/p4standards.html |access-date=2022-03-31 |website=www.clag.org.uk |language=en-GB}}</ref> The gauge of track built to these standards is 18.83&nbsp;mm.  Along with EM Gauge It is also a popular choice for finescale modellers working today.  The main advantage of P4 over the other 4&nbsp;mm standards is that the wheel flanges are approximately to scale and the flangeway gaps on P&C work are also close to scale.  This is most noticeable in photographs of the model where in many cases is it almost impossible to detect that you are looking at a model, as opposed to the real thing.  The disadvantages of near to scale flanges and flangeway crossings are that the trackwork has to be laid and built to very close tolerances and needs to be flat.  If this is not the case then the reliability of rolling stock on the trackwork is compromised leading to poor running and derailments.  This problem can, to an extent, be mitigated by the use of some form of suspension system in the locomotives and rolling stock used on the layout. There are different ways to do this and reference to one of the societies supporting modelling to this standard is recommended.{{According to whom|date=February 2024}}