Martin R. Baker, Senior Vice President at Greenbrier Companies (NYSE:GBX), executed a substantial insider sell on October 30, according to an SEC filing. What Happened: A Form 4 filing from the U.S. Securities and Exchange Commission on Wednesday showed that Baker sold 8,285 shares of Greenbrier Companies. The total transaction amounted to $517,771. In the Thursday’s morning session, Greenbrier Companies’s shares are currently trading at $60.64, experiencing a down of 1.03%. Unveiling the Story Behind Greenbrier CompaniesGreenbrier Companies Inc designs, manufactures, and markets railroad frei…