P4 Myths

Introduction

This section is for some of the myths that abound which often turn people off P4. Some of them started with a part truth, but have been twisted and changed and now make P4 seem a lot more difficult than it really is, others are just plain rubbish, probably started by someone with no experience of P4 modelling.

If you know of a myth you think should be included, or know something that could be a myth because it makes P4 seem difficult, please contact me so I can add it to the site.

Please scroll down the page or pick a myth from the drop down list on the left.

P4 needs a minimum radius of 4 feet

This myth came about as a result of someone saying that trains look better on a large radius curve, and of course it is true in that respect.

However, there is no reason why P4 models won't run on a tighter radius curve, I know this from personal experience, as I run my models on curves as tight as 3 feet diameter, without gauge widening. Such tight curves do not preclude the use of larger locomotives such as pacifics, loco's I run include such models as a BR standard 4 tank, and Merchant Navy, as well as smaller loco's of course.

Some models may require slight compromises in order to run on such curves. I have found that to run a model on a given radius on P4 requires no more, and in most cases far fewer compromises than would be required in 00 (EM is a differant matter, to run models on tight curves in EM most models will need many more compromises than would be necessary in P4).

I know what you're thinking, "but P4 is about rejecting all compromises" actually it isn't, P4 is about minimising the compromises in a model by using the correct gauge and wheel standards, what you do outside of these parameters is no differant to any other model built to a scale of 4mm/foot.

This is my Bachmann 4MT tank running in on my test track, I had a bit of an experiment with this loco, I converted it to P4 by reprofiling the original driving wheels and mounting them on longer axles, the pony and bogie wheels are from Alan Gibson.

The curve is 18" radius.

It is more difficult to convert ready to run models to P4 than EM

I don't know who came up with this one, because it is utter rubbish. Most P4 conversions can be done by simply replacing the 00 wheels with P4 ones. If you can't fit P4 wheels in, then there is no way you could fit EM wheels in, as EM uses wider wheels then P4. This also means that some models are easier to convert to P4 than EM.

The picture shows an EM wheelset (upper) and P4 wheelset (lower), these are exactly the same wheels from the same manufacturer, if you look closely you will see the EM wheelset is marginly wider over the wheel faces compared to the P4 wheelset, there isn't a big differance but it can be enough to make EM conversion difficult where P4 wheels would just drop in.

You will most probably need (or at least want) to move the brake gear out to line up with the wheels, but this isn't really an issue as you need to do this with EM as well. In fact on some models you may even need to do it with 00!

Ah yes, but what about springing? Well you can spring them if you want, it isn't necessary though, if you think that P4 models MUST be sprung I suggest you look at the myth of You have to spring everything in P4.

You have to work to hundredths of a millimetre in P4, you don't in 00 or EM

This is a part truth, yes you do work to hundredths of a millimetre in P4, but you do in EM and 00 as well. Confused? Allow me to explain,
P4 has a track gauge of 18.83mm, alot of people look at that, see 2 decimal places and panic! Because they don't think they can work to such accuracy, however it doesn't need to be any more accurate than EM which has a gauge of 18.20mm, or 00 which has a gauge of 16.50mm. Notice I added more digits to the EM and 00 gauges than is normally used? The point is that regardless of what gauge you use, the track has to be exactly that gauge.

What's more, you don't actually measure these dimensions anyway. If you buy a length of ready to lay flexi-track for 00 you don't need to measure the track gauge, do you? It is exactly the same for P4, buy the track, lay it, and run your trains, no measuring required. But what about points? You have to handmake the points, so you need to measure them. No you don't, you buy a set of gauges, and use them to build your points, no measuring required. In fact you don't need gauges at all with some recent P4 point kits, try doing that in another gauge.

P4 doesn't require any more accuracy than 00 or EM, however it is more accurate to scale than 00 or EM. A failure to understand the differance is what causes this myth to continue.

It is more difficult to build pointwork in P4 than 00 or EM

Actually, it's easier! There are 2 reasons for this:-

1. The P4 Track Company now produce point kits which are as easy if not easier to build than most plastic wagon kits, These kits are only available in P4 , so to build points in any other gauge you will have to start from scratch.
2. Even if you don't use the kits mentioned above you will find it alot easier to build pointwork in P4 than 00 or EM because of the correct scale dimensions of P4. 00 or EM has the problem of too narrow a gauge combined with too wide flangeways, this means in some formations you run out of space for all the rails, and often have to compromise on rail lengths or just miss a rail out altogether. You don't get this problem with P4 because it uses the correct scaled down dimensions of the fullsize.

Pointwork takes up 30-40% more space in P4 than 00 or EM

Another part truth, P4 and EM pointwork is about the same length, give or take a millimetre. 00 pointwork will typically be around 12% shorter than P4 pointwork, the reason for this is simple 00 pointwork is actually built to H0 scale (3.5mm/foot), while P4 pointwork is built to 4mm/foot. This means that if a point is 200mm long in 00, it is 224mm long in P4. Having said that I have built P4 points in the past by converting Peco 00 points (by soldering the Peco rail to PCB sleepers), there is certainly no differance in length there!

I think this myth mostly comes from the idea that you need larger radius points in P4 than 00 or EM, which is much the same as the myth that P4 needs a minimum radius of 4' which can be seen on the previous page.

You have to spring everything in P4

No you don't. Provided your track and chassis/underframes/bogies aren't twisted you don't need to spring or compensate your models. It doesn't have to be perfect, the odd dip or bump won't cause any problems.

Having said that, long rigid wheelbases are not recomended, so it is best to spring or compensate any vehicle with a wheelbase over 50mm (12'6"). It is also best to allow the middle axle on 6 wheeled models (loco's, tenders, coaches, etc.) a little vertical movement, with a light spring on the axle (a length of 0.010" piano wire does the trick) to push it into any dips. The average 4 wheel wagon does not need springing or compensation, neither do most bogies, in fact I haven't found it necessary to compensate 6 wheel tenders either.

The most common reason a vehicle derails is insufficient weight, ensure that your wagons weigh around 40-60grams and coaches and bogie vehicles weigh around 100-150grams, a general rule of 20-30grams per axle will ensure your trains run smoothly.

It takes longer to build a model to P4 than 00 or EM

This myth is based on the idea that you need to spring everything in P4, if that were true then it probably would take longer, see the section for you have to spring everything in P4. Also I have recently built a loco kit to 00 gauge, I had to make several modifications to the gearbox in order to get it to fit between the frames, none of these modifications would have been necessary in P4. So it actually took longer to build this model in 00 than it would in P4.

You have to scratchbuild/kitbuild more in P4 than 00 or EM

This isn't true at all, unless you are comparing to 00 course scale (there are at least 4 standards in 00). With 00 course scale you can buy ready to lay pointwork, but if you want the correct sleeper spacing and geometry you have to scratchbuild, even in 00 course. As previously mentioned though you can buy easy to assemble point kits in P4, these aren't available in any other gauge, so P4 is easier in that respect.

As with any other gauge, to model in P4 you just have to swap the wheels in 00 models for P4 wheels. There may even be places that can do this for you, however I am not aware of any at the moment. (If you offer this service please contact me so I can add you details to the site.)

It is true that more people scratchbuild in P4 than the other gauges, the reason for this is simple, if you're going to go to the effort of scratchbuilding you might as well build the model to scale!

So basicly,
You don't have to scrathbuild or kit build in P4 anymore than you do in 00 or EM.
There are more people who scratchbuild or kitbuild who choose to build their models to P4 than 00 or EM.

Again a failure to understand the differance is what causes this myth to continue.

P4 is more maintenance intensive than 00 or EM

I don't know what the origin or this myth is, but it's rubbish!

There's 2 major parts to this myth that I have heard, apparently both stemming from P4's use of a scale flange.
Because P4 uses a scale flange,

1. the track work has to be continually tweaked and adjusted to prevent derailments.
2. the wheels have to be cleaned more often, as any dirt on the wheels will build the tread up and make the flange smaller or non-existant.

For part one I'll use my test track as an example, this was previously mentioned in the minimum radius myth where there is a picture of it. I built this around 18months ago using C&L flexitrack, and apart from having to replace a section of sleepers when someone stood on it and ripped a short length of rail out of the chairs I have never had to tweak it. I should also mention that the alignment isn't as important as some people would have you believe, my test track is truely awful - it has dips, humps, lumps missing out of the rails, and dogleg joins, at one join the rails aren't joined together at all just a piece of wire to maintain electrical conductivity!

My usual response to part two is "you mean you're supposed to clean the wheels?" I haven't cleaned mine since I painted them, and on some stock that was a couple of years ago!

Just like every other scale and gauge some maintenance is always going to be necessary, but no more is necessary in P4 than any other gauge.

You can't build large layouts in P4, P4 layouts have to be small shunting layouts.

According to this myth P4 requires so much work that it would take too long to build a large layout, and so you have to build a small layout in P4. This stems from a number of the other myths, such as it is harder to build points in P4, you have to spring everything in P4, it is harder to convert models to P4, and so on. If you have read the sections for these myths then you will know that these aren't true, and as a result there is no basis to this myth whatsoever.

There are large P4 layouts around which further disprove this myth, because if someone has built a large layout in P4 then clearly it is possible, and practical.
Some examples of large exhibition layouts in P4 are:-

• Aberhafren
• Slattocks Junction
• Bonnybridge Central

As well as numerous layouts built in lofts, and of course test tracks in the area groups of the Scalefour Society, some of which are truely massive!