CYNICS will say Nottingham has enough of a problem finishing off Tram Routes 2 and 3 without worrying about Route 4. But given the bewildering lengths of time it takes to plan and execute major engineering projects in the United Kingdom, it's never too soon to be asking what happens next.
Ponderous strategic planning might be a thing of the past if governments stop talking about investing greater powers in the regions and actually do something about it.
Meanwhile there is no need to wait for passenger analysis on the two lines whose opening has been delayed until early 2015.
Aside from an odd blip two years ago, business on Line 1 has been a massive success. Notwithstanding all the justifiable complaints from Beeston about the impact of construction, the second and third lines will be equally successful.
Last night Broxtowe councillors were looking at the feasibility of a fourth line that would extend the Phoenix Park spur to Kimberley.
It's been talked about before and it makes sense, offering relief to road users on the A610, with its bizarre new speed limits, who have no alternative railway transport this side of Langley Mill.
Compared with the challenges of Beeston, a Kimberley line looks like a penalty kick.
Strategic thought on tram development must also take account of the explosion in green belt housing developments that will take place over the next decade.
Which is why the time to be talking about the next tram routes is not tomorrow, but today.