Up to 21/22 passengers standing in the large vestibule (as
pdeaves also relates above), or up to 14 in the small one, on a Voyager out of Birmingham is the maximum I have to endure on my normal evening commute home these days. A worse experience in similar conditions was travelling back the day after a gig in Banbury with a hangover in the middle of the snow disruption in December 2010, where the first train I'd boarded (a 2-car Chiltern 165) had struggled as far as Leamington Spa, where we were turfed off and onto the following packed Voyager into Birmingham, as I anxiously watched my previously ample one hour connection time into my next train from New Street disappear into the ether (made it with about ten minutes to spare, as I recall).
I've been on a Pacer sufficiently overloaded with standees that it simply ground to a halt and stuck while attempting to negotiate the Gateshead curve: The resigned tone of the guard as he relayed over the PA the nature of our predicament, and the drivers dexterous control of the power handle as he attempted to nurse our stricken beast around the curve, suggests that this was not an isolated incident. Elsewhere in Northernland, the last train out of Manchester back to Macclesfield on a Friday or Saturday night is often heaving to the gunwhales with as many standing passengers as you can accommodate in the vestibules and down the aisles of a capacious 323 unit, and "ample liquid refreshment" is essentially compulsory.
Speaking of which, I've been extremely glad that I
haven't been travelling on some evening Transpennine services northbound out of York towards Middlesbrough that I've witnessed with some truly nightmarish loadings on, including some distinctly agitated (and definitely intoxicated) passengers, where crowd control barriers have been employed simply to keep the crowds from spilling over the platform edges before they board.
Overall, though, I tend to avoid the worst overcrowding, as where possible I will wait for a following train if the one presented before me looks too busy: Not always an option, though, if my journey is time critical and the service is only hourly, or its' the last train of the night.