The Oregon Zoo Railway is one step closer to being recognized nationally as a piece of history.

The State Advisory Committee on Historic Preservation Friday recommended that the railway be nominated for the National Register of Historic Places, though with a revision first.

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Washington Park and Zoo Railway is a star attraction for adults and children alike. Laurie Isola / OPB

The committee said the railway’s nomination report, written by Portland researcher Melissa Darby, must be revised to more accurately reflect a “period of significance” in the railway’s history.

The currently proposed period spans the year the railway was built, 1958, until the end of the baby boom era in 1964.

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“The committee felt that the end date of the period of significance, 1964, should more accurately associate with a major event related to the significance of the zoo train,” Robert Olguin with the State Historic Preservation Office said.

“National Register guidance explains that period of significance is the length of time when a property was associated with important events, activities, or persons, or attained the characteristics which qualify it for the National Register listing,” he said.

Related: What Will It Take To Get The Oregon Zoo Railway's Long Route Back On Track?

Once the revision is made, the nomination will be forwarded to the National Park Service to consider whether to list it as a historical site.

If accepted, the historical listing would include the full 2-mile route of the zoo train through the Oregon Zoo and Washington Park, which was cut short in 2013 due to landslides.

Since then, the train has been running a 6-minute trip only through zoo grounds, and community members have been trying to gather support to restore the full route.

According to the State Historic Preservation Office, some benefits of listing a property in the National Register include a federal tax program that can save property owners 20% of the cost of rehabilitating their income-producing property.

Owners of listed properties can also apply for “Preserving Oregon” grants, in which the State Historic Preservation Office will award historic properties up to $20,000 for rehabilitation work.