So Alex -
Lets move you on a step.
Take a moment or two to identify exactly what it is about the train that gets you jittery and why. Then if it is something irrational and is the result of a preconception / scaremongering then debate it out within your head and may the most rational and logical side win.
If you cannot identify it - talk yourself into refusing to give it any further thought until it can identify. Like you would a child who is just whining .
With the blood giving - ensure you're well fed and hydrated and not hung over pre going to minimise any wierd feelings.
Have a good trip tomorrow.
take some thing academic (but not too heavy) to read - journal- to read and bury yourself in it if you do get a bit jittery.
Meg
'There can only be true courage when first there is genuine fear'
Dr.David Livingstone