While Parker v South Eastern Railway [1877] 2 CPD 416L related to an exclusion clause the judgement was framed in terms of a generic contract cause and it is accepted (most notably by the superior courts of record) as the authority of the applicability of any type contract term in an unsigned contract.
Note the use of the term "condition" not "exclusion condition" in Mellish LJ's ruling:
I am of opinion, therefore, that the proper direction to leave to the jury in these cases is, that if the person receiving the ticket did not see or know that there was any writing on the ticket, he is not bound by the conditions; that if he knew there was writing, and knew or believed that the writing contained conditions, then he is bound by the conditions; that if he knew there was writing on the ticket, but did not know or believe that the writing contained conditions, nevertheless he would be bound, if the delivering of the ticket to him in such a manner that he could see there was writing upon it, was, in the opinion of the jury, reasonable notice that the writing contained conditions.
It established 2 important principles: that evidence that a party had actually read a contract term is not required to make it binding, but that the existence of contract terms must be notified to the customer.
Olley v Marlborough Court Hotel [1949] 1 KB 532 is significant in that said notification must take place prior to the contract being formed or it is void, unless there is a history of consistent prior dealings that means that the part should have become aware that the terms were normally in place.
What this means for the railways (in my opinion) is that new passengers must be made aware of the existence of the NCoC (such as by way of a prominent notice displayed at the point of purchase - I forget the authority but the principle that a prominent notice at point of sale or entrance is sufficient is well entrenched in common law), and must be able to access to the full text prior to completing any purchase. But that long term regular passengers may be bound even if this is not the case. A notice issued after the contract was completed (for example a sign at a platform or on the back of a non-refundable ticket) is not sufficient.
As Dave notes Spurling vs Bradshaw (1956) warns that unreasonable or onerous clauses must be notified much more prominently (the "red hand rule"). As we are in the realms of common law, given the lack of case law examining the NCoC, it is by no means clear what kind of bar would be applied by the courts when determining what was onerous or unreasonable.
EDIT: Unfortunately from the point of view of the consumer Common Law is much less "user friendly" than most consumer statutes and in practice that makes relying on this stuff a very different and more difficult and potentially expensive proposition from dealing with a shop that sold you a faulty TV. IMO the fact that transport is excluded from most consumer law is quite disgraceful.
