YOU SAID:

Somebody told me once that I accidentally took the train the wrong way

INTO JAPANESE

誰かが私に誤って電車に乗ったのを間違えたと言ったことがあります

BACK INTO ENGLISH

I once told me that I accidentally got on the train

INTO JAPANESE

誤って電車に乗ったと言ったことがあります

BACK INTO ENGLISH

I once said that I got on the train by mistake

INTO JAPANESE

間違って電車に乗ったと言ったことがあります

BACK INTO ENGLISH

I once said that I got on the train by mistake