EM: Actually, if you just do two things,
you can get to approximately
an order of magnitude improvement,
and I think you can go beyond that.
So the first thing to do
is to cut the tunnel diameter
by a factor of two or more.
So a single road lane tunnel
according to regulations
has to be 26 feet,
maybe 28 feet in diameter
to allow for crashes
and emergency vehicles
and sufficient ventilation
for combustion engine cars.
But if you shrink that diameter
to what we're attempting,
which is 12 feet, which is plenty
to get an electric skate through,
you drop the diameter by a factor of two
and the cross-sectional area
by a factor of four,
and the tunneling cost scales
with the cross-sectional area.
So that's roughly a half-order
of magnitude improvement right there.
Then tunneling machines currently tunnel
for half the time, then they stop,
and then the rest of the time
is putting in reinforcements
for the tunnel wall.
So if you design the machine instead
to do continuous
tunneling and reinforcing,
that will give you
a factor of two improvement.
Combine that and that's a factor of eight.
Also these machines are far from being
at their power or thermal limits,
so you can jack up the power
to the machine substantially.
I think you can get
at least a factor of two,
maybe a factor of four or five
improvement on top of that.
So I think there's a fairly
straightforward series of steps
to get somewhere in excess
of an order of magnitude improvement
in the cost per mile,
and our target actually is --
we've got a pet snail called Gary,
this is from Gary the snail
from "South Park,"
I mean, sorry, "SpongeBob SquarePants."
EM：实际上，如果你只做两件事，你可以得到大约一个数量级的改进，我认为你可以超越这个数量级。因此，首先要做的是将隧道直径减少两倍或更多。因此，根据规定，一条单车道隧道的直径必须为 26 英尺，也许是 28 英尺，以允许碰撞和紧急车辆以及内燃机汽车的充足通风。但是，如果你把这个直径缩小到我们正在尝试的直径，即12英尺，这足以让电动溜冰鞋通过，你就会把直径降低两倍，横截面积减少四倍，隧道成本与横截面积成比例。所以这大约是半个数量级的改进。然后隧道掘进机目前在隧道掘进一半时间，然后停止，然后剩下的时间对隧道壁进行加固。因此，如果您将机器设计为进行连续隧道和加固，那将为您提供两倍的改进。把这些结合起来，就是八倍。此外，这些机器远未达到其功率或热极限，因此您可以大大增加机器的功率。我认为你至少可以得到两倍的改进，也许是四到五倍的改进。所以我认为有一系列相当简单的步骤 要使每英里的成本提高一个数量级以上，我们的目标实际上是 - 我们有一只叫加里的宠物蜗牛，这是来自《南方公园》中的蜗牛加里，“我的意思是，对不起，”海绵宝宝“。
