Mattel Inc. on Monday said that it signed an agreement to buy HIT Entertainment, the company behind Thomas the Tank Engine and Bob the Builder. The deal is valued at $680 million.

The El Segundo toy maker’s is buying London-based HIT from a consortium led by private equity firm Apax Partners. The deal is Mattel’s biggest acquisition in about a decade.

“Mattel is the right home for Thomas & Friends,” Chief Executive Robert Eckert said in a statement, citing his company’s global marketing and distribution and HIT Entertainment’s international programming and licensing expertise.

Mattel already markets die-cast and plastic toys of Thomas & Friends characters – based on a popular British children’s TV series – under a license that has produced global sales of more than $150 million.

The deal also will help replace Mattel revenue in the pre-school segment it will lose when Hasbro Inc. takes over the license for Sesame Street products next year. Mattel had held that license for many years.

HIT has more than $180 million of revenue and the purchase price represents 9.5 times the company’s earnings before interest, tax, depreciation and amortization, according to Mattel. The acquisition, which will be financed with a combination of cash and debt, is expected to close early next year after an antitrust review.

Shares were up 63 cents, or 2.3 percent, to $28.32 in midday trading on the Nasdaq.