Going in no particular direction

IMHO on lines such as the Jubilee, if the T/Op wants to make an announcement as to where the train terminates, it is less confusing to the passengers to leave out which direction of the compass the train is traveling. The in car line maps are straight left to right and visa versa.

"This is a Circle Line train to here"
"This train is for Hammersmith via five trips around the circle line"
"This is a Cricle Line train to everywhere"
"Welcome to the magical mystery tour of the Waterloo and City Line"
"This is a Waterloo & City Line train"
"This is a District Line train to your guess is as good as mine"

I remember an anacronym (if I've spelt that right) I saw years ago to describe the direction of travel used.

OUSE & WIND

Outer
Up
Southbound
Eastbound

and

Westbound
Inner
Northbound
Down

Its still used in the Network Rail PTS handbook.

In giving a warning of an oncoming train the lookout will blow his whistle and indicate the road by the number of blows. Once for OUSE and twice for WIND.

I don't know how it works on NR. I recall on LU seeing groups of two on the track before - does this still happen or are the groups generally bigger now?

I don't know what happened in the past, but this is how it works now:

On LUL: Train op see's workers on the track and blows whistle. Track workers move to a place of safety, then acknowledge the train.

On NR: Train op see's workers on the track and blows the whistle. Track workers acknowledge the train, then move to a place of safety.

In both cases, if the whistle is not acknowledged, the emergency brakes will be applied.

They have one opportunity to make an acknowledgment, there are no second chances!!

Yeah, they always do that