Markits Irish Broad gauge axles.

[Mayner]

The owner of Markits has been in contact to advise that he is currently manufacturing axles for OO & EM and would be prepared to manufacture axles to suit the  Irish Broad Gauge.

This brings up few questions in considering if the idea is worth pursuing

1.  Track & Wheel Standards. 21mm to OO standards or a reduce the gauge to 20.2 as advocated by Martyn Wynne or even 20mm to allow the wheel sets fit without having to within having to widen the body on the majority of Irish inside cylindered steam locos or move out the cylinders and outside valve gear on more modern locomotives

Reducing the gauge to 20.2mm  or possibly 20mm and adapting OO gauge standards would also allow increased sideplay (slop) between wheels and chassis. This would remove one of the major barriers to Irish Broad gauge modelling fitting a continuous run layout into the average Irish bedroom or garden shed.

2.  Demand. Is there sufficient demand for a Markits "Irish OO" gauge axle to commission an order of 500-1000 driving axles?

3. Take up of broad gauge modelling. Is the lack of a Markits "Irish Broad Gauge axle a significant barrier to people modelling the wider gauge.

3. Potential level of interest in an Irish OO gauge. Would more people be interested in taking up broad gauge modelling if a continuous run layout could be fitted into the same or slightly large space than a similar OO gauge layout?

 

Running clearances Markits wheelsets and some loco kits.

A high proportion of 21mm gauge modelers work to EMF or P4 wheel and track standards.

 Markits wheels are designed for OO gauge use and are wider than the 2.28 maximum recommended for EMF.

This leads to essentially the same problem that lead to the adaptation of British N, TT and OO gauge due to limited/negative clearances between wheels and splashers or valve gear on outside cylinder locos even when the back to back is set to 19mm to allow OO gauge clearances.

	Track gauge	21mm	21mm	20.3mm (Martyn Wynne Irish EM)	20.3 mm(Irish OO?)
	Standard	OO	EMF	EMF	OO
Back to Back		19	19.3	18.6	18.3
Markits wheel width	2.5	5	5	5	5
Overall width wheelset		24	24.3	23.6	23.3
Loco	Width between splashers	Clearance	Clearance	Clearance
TMD/SSM J15	24.3	0.3	0	0.7	1
TMD/SSM S	28	5	3.7	4.4	4.7
SSM GG/SG2	25.3	1.3	1	0.7	2
JMD 650/Ks	26	2	1.7	2.4	2.7

 

Edited January 18, 2019 by Mayner

[Andy Cundick]

I'd certainly be up for some.I've never checked the back to back of my stock having relied on my faithful gauge i bought from Terry McDermot 30-40 years ago,its turns out to be 19.7mm,so far i've had no issues with clearances on the 20 odd locos i've built so far.Andy.

[merlinxlili]

John,

A great initiative, again! There is no doubt that the Markits wheels are wonderfully easy to mount and ready quartered, so having that advantage available for Irish railway modellers using 21mm would be a big bonus.

However when we begin to talk about introducing another variant on the gauge, I am not so happy. When you described a comprehensive specification for 21mm EMFine track and wheels last year,  I concluded that this is an excellent compromise, especially since it transpires that quite a few of the people who have modelled in 21mm seem to have used that system instead of the more rigorous P4 specifications. I suppose that I am lazy but I feel that EMF would provide most of the delicacy and broadness of Irish track, while significantly reducing the amount of work required to build and maintain a 21mm railway, compared with P4. So far so good. But the number of people who pursue 21mm in some form is painfully small, so I believe that we should avoid multiplying the number of gauge possibilities in order to concentrate whatever supplier interest we can muster. 

Also, probably a silly suggestion. You have identified that there appear to be risks from using 5mm wide wheels with the EMF track gauge. Since we are  talking about building kits, is it so big an extra job to modify the splashers, etc? Alternatively what about getting the Markits wheels machined down to reduce their width? Arranged by the modeller I mean, not Markits.

That is my two ha'pence-worth. Once again, I fully support your efforts to find a way of making 21mm modelling easier and not so scary. The adage that the last 10% of achieving perfection costs 90% of the effort is probably exaggerated, but carries a great deal of truth for me.