My advice based on thirty years of layouts in lofts and air conditioned rooms is to leave out the rail joiners, leave a 0.5-1mm gap between rail ends on a normal temperature day, and THEN join the rail lengths (as required, allowing for section breaks) like this:
I use garden 'rose' wire (B&Q or your garden centre - the kind used by flower arrangers) which is tinned and flexible (stronger than fuse wire) and make a complete loop (round a small file) in a short length; the ends of this loop are soldered to the rail ends. The loop will allow expansion and remove stress from the soldered joint. The thing will work better if you lightly tin the rail as well. A quick dab with a small iron and Robert's your father's brother. It is similar to the way track circuit wires are done full size. My current layout has used this method for twenty years with no failures. Fishplates are not reliable conductors of electricity as you will find out when showing your layout off to club members.
It has other uses this wire- holding things together while the glue dries, and for soldering awkward parts. One bobbin will see you out.
Alistair Wright
'5522' Models
I use garden 'rose' wire (B&Q or your garden centre - the kind used by flower arrangers) which is tinned and flexible (stronger than fuse wire) and make a complete loop (round a small file) in a short length; the ends of this loop are soldered to the rail ends. The loop will allow expansion and remove stress from the soldered joint. The thing will work better if you lightly tin the rail as well. A quick dab with a small iron and Robert's your father's brother. It is similar to the way track circuit wires are done full size. My current layout has used this method for twenty years with no failures. Fishplates are not reliable conductors of electricity as you will find out when showing your layout off to club members.
It has other uses this wire- holding things together while the glue dries, and for soldering awkward parts. One bobbin will see you out.
Alistair Wright
'5522' Models