UPDATE 1-Neenah, which sells manhole covers, is bankrupt

* Neenah files Chapter 11, revenue under pressure

* Noteholders agree on restructuring accord

NEW YORK Feb 3 (Reuters) - Neenah Enterprises Inc NENA.OB, a large independent seller of castings such as manhole covers and storm grates to municipal governments, filed for bankruptcy protection on Wednesday and said it has reached a restructuring accord with many debt holders.

The Neenah, Wisconsin-based company and 17 affiliates sought Chapter 11 protection with the U.S. bankruptcy court in Delaware. Neenah said it had $286.6 million of assets and $449.1 million of debts as of Sept. 30.

In a court filing, Neenah said a drop in public sector spending, a slowdown in infrastructure spending associated with commercial and residential development, and "dramatic declines" in heavy-duty truck, construction and farm equipment markets hurt profit and cash flow. Neenah said the bankruptcy will help it and its affiliates address "immediate liquidity needs."

The company said holders of 55 percent of its 9.5 percent secured notes maturing in 2017 and all of its 12.5 percent subordinated notes maturing in 2013 have agreed to support a planned reorganization.

It said this plan calls for the secured notes to be swapped for 97 percent of newly issued common stock plus $50 million of new secured notes and for the subordinated notes to be swapped for 3 percent of the new common stock plus warrants. Holders of existing stock would be wiped out, it said.

A hedge fund, Tontine Capital Partners LP, owned 58 percent of Neenah's diluted shares as of Dec. 4, 2009, a regulatory filing shows.

The case is In re: Neenah Enterprises Inc, U.S. Bankruptcy Court, District of Delaware, No. 10-10360. (Reporting by Jonathan Stempel; editing by Andre Grenon)