GL5 Forum

Hello my name is David Roberts I'm new to GL5 and it's my first time to enter anything on this forum I'm interested in 5" gauge steam I'm hoping to build a small garden raillery using 16mm aluminium rail I've started building a small locomotive and I'm hoping to finish it but I only started it 36 years ago I purchased a small metal turning lathe and would like to purchase a milling machine in the near future.
I don't know if I can attend GL5 activities health problems restricts the distance I travel and I'm living in Carmarthenshire Wales.
I would like to ask for help could somebody tell me please what is the maximum gap I should allow between the ends of rails during coldest of winter I don't want to gaps to be too wide but I don't know what I should allow during expansion the ends will come together and move the track out on the curves I can observe this and add extra joints as needed is this making sense or am I taking it too seriously.
The back to back wheel measurements how critical is this is it stuck to only the wheel measurements on the locomotive I'm building so narrow it is possible to reduce this but the flange width will be quite small does this make cast iron wheels vulnerable to damage.
Thank you all very much
David Roberts

Hi David, and welcome.
Hopefully someone else will answer the rail question, but regarding the back to back, the figure quoted in our standards (4 11/16) is the required dimension for new construction, but our track will accept wheelsets with a back to back of 4 5/8, though this is an absolute minimum. So, if your loco has a back to back somewhere between 4 5/8 and 4 11/16, it should be fine.
Dave.

Hello Dave thanks for coming back to me and I think the way forward is to alter my wheels to comply with GL5 standards.
Coming back to the question of the Gap between the ends of rails could somebody recommend a book or literature of some kind covering this topic of track building using 16mm aluminium rail a detailed description of building points would also be very welcome.
Thank you very much
David Roberts

Hi David,

I have the Rideonrailways / PNP Railways aluminium Rails + Plastic sleepers. These are joined by fishplates with absolutely no gap.
Expansion/contraction causes the traks to move a few mm during summer and winter and this has never caused any problem so far.

Holger

Hello Holger thank you for your reply but this is saying the opposite to my understanding of aluminium rail. Butting in the joints together would make things much easier PNP railways has a lot of experience this is very interesting thank you very much.
David Roberts

David, I strongly suggest not butting the rails up tightly to each other. It will depend to some extent on how you lay the track, whether there is any give in it. The track at Gilling is screwed to a concrete base, and even though they were very careful building it, it still buckled a few years ago and formed a loop. Mind it was hot, they also had to water the turntable to shrink it so that it would turn again.
The Linsey track I think is also on concrete, and as far as I know hasn't had that problem, but they also have sliding expansion joints in places.
Remember, fishplates should not be bolted up tight, and the coefficient of thermal expansion of aluminium is around 24 x 10^-6 per degrees C.

Hello admin
thank you very much for your feedback I realise the fish plates needs to be loose to allow expansion and I would also like to ask please is there any information on how the sliding expansion joints were constructed.
Thank you very much
David Roberts