The firm, which is owned by private equity firm Kingsbridge Capital Advisors and Goldman Sachs Group filed for insolvency after banks declined to extend loan facilities.
Operations will continue as usual during the insolvency process as the company seeks to implement a rescue plan.
Maerklin, which began production in 1859, has factories in Germany and Hungary, and employs 650 workers. Revenue last year was €128m ($165m).
The company made a net loss of about €20m in 2008 and has debts of “at least” €50 million at banks including Landesbank Baden-Wuerttemberg according to sources.
It is presenting about 400 new products at Spielwarenmesse.