、。
Some traveled by train, others by car.
Literal
Train [by-で] trip [object-を] do people [exist-conditional-ば], car [object-を] use people [too-も] existed.
The ~もいれば~もいる ('some do X, and others do Y') is a common contrastive pattern using the conditional form いれば of いる ('exist, be'). Literally 'if there are those who X, there are also those who Y,' it enumerates coexisting groups or behaviors. The ~ば here isn't a real conditional but a coordinating device.