I have to assume you started a property management firm whereby you are managing rental properties for other property owners (e.g., a property management business).
In that event, you can look at using Section 179 to deduct the cost of the trailer if you wind up meeting the business income requirement.
See https://www.irs.gov/publications/p946#idm140334975111520
Otherwise, you can look at using the Special Depreciation Allowance (SDA - aka bonus depreciation) to expense the trailer.
See https://www.irs.gov/publications/p946#idm140334973797184
