Signese

One of these days I'll look up what 怠 means, but that seems like too much work right now. B)

"At idle speed", huh.

No idea about the antonym, though.

Something tells me the antonym is not 怠速外. Maybe 忙 速中?

Consider 常速中.

Humm, I'll consider it. However, google only has 41 hits for that phrase (it says more, but if you go past page 4 it says only 41), most of them are related to VOA, and many of the others have a punctuation marking in the middle (e.g. 常速、中速和高速). So while it's foolish of me to disagree with you, it doesn't pass my normal test.

So roddy, what is the answer?

My other guess is 運行中?

Oh yes, the bit where I'm meant to come back and tell you the answer. The other one (going in the same direction, btw) was 急速中.

That sounds scary. I'd rather take the one says 怠速中.

I agree that 急速中 sounds scary.