Complex sentence: The design was purchased from the Swiss company Schweizerische Industrie Gesellschaft (SIG), who were contracted to build the first 10 before turning over construction to OTDC, subcontracted at Hawker Siddeley's CC&F factory in Thunder Bay.
Split into simpler sentences: The design was purchased from the Swiss company Schweizerische Industrie Gesellschaft (SIG). SIG was contracted to build the first 10 before turning over construction to OTDC, subcontracted at Hawker Siddeley's CC&F factory in Thunder Bay.