From the website: "Is there a strict dress code? Although many men choose to wear a suit or sport coat, they are not required. We do request a “Nice Casual” attire, such as Dockers and a nice shirt or sweater for the men and slacks and top or casual dress for the ladies. This is your evening to relax and enjoy yourself, but it should also be special."
Some trains do like a slacks dress jackets if you go into the dock station there are pamphlets with more information and you can find out on their website
Thanks! Your answer is awaiting moderation.