The top 10 most overcrowded trains in England and Wales will be an average of more than 225% in excess of capacity by 2022, according to the Labour Party.
Analysis of recent Department for Transport figures shows the typical load factor of the 10 most crammed services increased from 159% to 190% over the past six years.
If this trend continues to when the current parliament is scheduled to end in 2022, the 10 most overcrowded trains will be 227% in excess of capacity, Labour said.
The party is calling for train companies to be brought back into public ownership.
Shadow transport secretary Andy McDonald said: "Overcrowding on our railways is fast becoming a national disgrace thanks to the Tories.
"It will come as little surprise to long-suffering commuters to hear that overcrowding on trains has reached record levels, but the bad news is that it's set to get even worse.
"At the current rate some of the most vital commuter routes in the country will be appallingly cramped by the end of this parliament."
Mr McDonald said passengers should not have to suffer being "crammed into dangerously full carriages as part of their daily commute" and claimed they are "paying more for less under the Tories".
Southern Railway's 7.16am train from East Grinstead to London Bridge is the most overcrowded train with an average of 1,366 people rammed into a dozen carriages designed for just 640.
Next year's increase in the 40% of rail fares which are regulated will be revealed with the publication of July's retail prices index (RPI) measure of inflation on August 15.
The Government uses the figure to decide price increases for fares such as season tickets on most commuter routes and some off-peak return tickets on long-distance journeys.