As the RMT union rejected another offer on commuter routes served by Connex South East, the Communication Workers Union denounced a 2% pay offer as a "pittance" and threatened action in support of 5% and a £300 a week minimum by late 2003.
Though far from being a return to the industrial nightmare that dogged past Labour governments the muscle-flexing shook ministers as Tony Blair returned from nearly a fortnight out of the country to the taunts of his critics.
The prime minister condemned strikes that have already hit South West Trains and industrial action on ScotRail as support grew for a passengers' revolt to highlight continuing delays to services.
Mr Blair said strikes were an "unacceptable way" to resolve grievances, urging all sides in the current wave of disputes to seek arbitration.
Acas remains in touch with both sides on SWT and the prime minister issued the call after Downing Street disclosed for the first time that the transport minister, John Spellar, had intervened over the weekend, speaking to all sides involved in an effort to persuade them to start talking.
In sharp exchanges in the Commons Mr Blair threw his full authority behind his transport secretary, Stephen Byers, and his long-term strategy for rescuing Britain's fast-collapsing rail network.
Though Mr Blair appeared to sidestep Iain Duncan Smith's public challenge to sack Mr Byers - or express explicit support for him across the dispatch box - aides later said he has "complete confidence" in his cabinet lieutenant.
But the jetlagged Mr Blair, facing his critics after six days in the Indian sub-continent and a family holiday in Egypt, took a hammering from angry opposition MPs despite repeatedly blaming the Tory legacy of under-investment and botched privatisation.
Government statistics suggested that rail delays cost £445m - £14.61 per passenger hour - last year. After Mr Duncan Smith had described the rail network as "descending into farce" during his absence, Mr Blair contrasted Tory criticisms with the party's ambition to cut public spending - a move that would gouge £60bn out of much-needed investment.
The Liberal Democrat leader Charles Kennedy also weighed in with a scornful attack on Labour's lost opportunities since 1997, and challenged the prime minister's claim that investment has risen sharply under Labour.
Peter Hain, the Europe minister, further fuelled the sense of crisis with comments in the Spectator that the government was not radical enough in its early approach to the railways. "We have the worst railways in Europe. We started transport investment far too late. It's an intractable problem."
He added: "The problem is that there have been decades of under-investment. It is like turning round an oil tanker. People have far too high expectations of what we can achieve in the short term."
The RMT has called strikes on SWT and Arriva Trains Northern later this month and the prospect of action on Connex grew after a 4.8% offer was rejected because drivers had been promised 7%.
The possibility of disrupted mail deliveries will have alarmed Downing Street and the CWU has the industrial muscle to close post offices.
Deputy general secretary John Keggie said: "Take home pay for most postal workers is less than £150 per week and is quite frankly disgraceful."
Consignia said it was "bitterly disappointed" at the union's decision to hold an industrial action ballot.
Mick Rix, leader of the train drivers' union Aslef, voiced support for the RMT which is seeking to match increases he has negotiated for his members. "I have to put this message to some people within the industry: 'Don't dare try it with Aslef because we are industrially more powerful'."
