SPur on St. Stephens Green
 

I noticed a single track spur on the green line today, it runs along the north of the green after dawson street, what's that for?

It can hold a single tram if required during disruption/events etc.

It'll mean trams can turn around at St Stephen's Green (if coming from Brides Glen / Sandyford) as now without blocking other trams going to or coming from the northside.

I'd say it will be quite likely that not all trams will go through the city from the southside and there will be a more frequent service on the southside where the service is well established.

There's also a junction at the end of O'Connell Street that enables trams to loop around the city without going to the northern terminus. Along with the connections with the red line, there are quite a lot of permutations now as to different journey possibilities, so it will be interesting to see what is offered.

Brides Glen to Parnell Street
Sandyford to Broombridge

It will more less be every second tram doing the different routing just like the Tallaght/Saggart running. You may see the odd Brides Glen to Broombridge at peak times similar to Point-Saggart.

The current SSG green points can be used for turning back, the spur will have almost no use like the Green/Red line connections.

I imagine the spur will be used to store trams between busier periods.

There may be untimetabled extra peak services (as there are now) between Sandyford and St Stephen’s Green that may use the siding to stable before returning south.

Transdev are not fans of leaving trams stationary in the city center, all peak trams currently route back to depot.

Possibly and I'm sure SSG-Parneel will have a lot more regular closures when it will be used.