Identify your audience. Audiences for choo-choo cards can vary from very young to very old.
Think about how you can include train-related language in the card. Phrases like "switching tracks" and "all aboard" can be used to pull the theme of the card into play. For example, a choo-choo card thanking a person's participation in an adult's graduation ceremony can be worded "Thanks for being all aboard on Frank's decision to switch tracks in life." Another example could be "Thanks for watching Frank get his one-way ticket for success."
Write in the choo-choo card. Physically write in the card or type in a text box online. Write the word "Dear" and then the person's name, followed by a comma. Add drawings of train-related items in the card. For example, draw some train tracks below your signature or include pictures of trains.
Use age-appropriate material related to choo-choo trains in your card. For example, if you are writing a choo-choo train card for a child, write something like, "I hope you had as much fun at my ceremony as you did on the train ride here!" If you are writing a card for an adult, write something like, "Thanks for helping me get on the right track to realizing my goals in life!"