idioms

[easy learner]

Dear Teacher,
In the following example taken from the cobuild dictionary of idioms which is used to explain the idiom (gravy train)

- Software companies realise that the gravy train can not go on for much longer. cut-throat competetion in the recession is sending computer prices tumbling.

what is meant here by (cut throat competetion and tumbling) ?

Anthor example

- The broadroom gravy train continued to roll happily along yeaterday.with news of pay off and awards to three ececutives totally nearly 104 million pounds.

what is meant here by the following :

- broadroom - roll happily along - pay off

[mykwyner]

cut-throatmeans without mercy or ethics.

tumbling means falling without control.

A boardroom is where executives of a company (board of directors) meet.

To roll happily along means to follow the same successful course you've been on.

pay off usually means bribe or other unearned payment.