WASHINGTON ( CNN ) -- President-elect Barack Obama 's January 17 train trip from Philadelphia , Pennsylvania , to Washington is intended to make the inauguration the most open and accessible in history . President-elect Barack Obama 's train ride from Philadelphia to Washington will pose myriad security risks . But it is also presenting the U.S. Secret Service with security problems . Miles and miles and miles of them . In addition to the well-publicized `` whistle stops '' in Philadelphia ; Wilmington , Delaware ; and Baltimore , Maryland , the Presidential Inauguration Committee says the public will have the opportunity to view the train at other locations along its 137-mile route . But the committee has not indicated where those sites will be , and the Secret Service has yet to release what security restrictions will be in place . Security experts say the train ride presents traditional threats to the VIPs on board , as well as countless buildings , homes and warehouses along the route . And there are non-traditional vulnerabilities : scores of bridges and tunnels that could be sabotaged . And , two environmental groups have warned , terrorists could take a page from al Qaeda 's playbook , using existing infrastructure , in this case chemical plants along the route , as an attack method . In a letter to the Secret Service , Greenpeace and Friends of the Earth wrote that they were worried that security efforts focused on the Obama entourage `` might not extend to the larger community which may suffer serious consequences in case of even one moderately successful terrorist release of ultrahazardous chemicals . '' `` We will be urging Mr. Obama and [ Vice President-elect Joe ] Biden to re-consider '' plans to travel by train , the groups wrote . In response , Secret Service spokesman Eric Zahren told the groups , `` Please be assured , the U.S. Secret Service is working closely with federal , state and local agencies to maintain a safe and secure environment for all of our protectees . '' Homeland Security Secretary Michael Chertoff , whose department includes the Secret Service , said he is confident of the agency 's abilities to protect the president-elect . `` Remember , the Secret Service has taken the president to Iraq and to Afghanistan , to some very hostile places around the world . I 'm comfortable that we have the skills , working of course with state and local authorities , to protect the president-elect in Pennsylvania and Baltimore and Washington , D.C. , '' Chertoff said . Chertoff said he is aware of the environmental groups ' concerns . `` I suspect it 's being done , frankly , largely as a public relations ploy , '' he said . `` I do n't think there 's any particular threat from chemical plants along the train route . '' iReport.com : Send your photos from the train stops . A former Secret Service agent said the agency has had experience with presidential train trips and said authorities typically install chemical , biological and radiological detectors along the route . Amtrak and the Secret Service will not say whether Obama 's train car will be armored , though experts say special cars have been used in the past . `` Security will be provided in the air , on the ground and in the water , '' said Amtrak Police Department Chief John O'Connor . `` It 's a daunting challenge , but there are many , many police departments that are working together to make this happen . '' Once the train reaches its final destination , the presidential inauguration itself will offer an attractive target for terrorists because of `` the historic significance of the nation 's first minority president , '' a U.S. intelligence assessment said . The report hastened to add that no specific threat has been detected thus far . The document says the swearing-in of the first minority president `` increases the potential threat , particularly stemming from individuals on the extremist fringe of the white supremacist movement . '' But it adds that no such groups are known to have threatened the inauguration so far . The report further noted that `` lone offenders '' not connected to organized groups pose the greatest potential threat because such offenders are often the most difficult to detect . The document says there have been some reports of lone offenders making threats but no indication that any of the potential threats `` have progressed past rhetoric to operational planning . '' CNN 's Carol Cratty contributed to this report .
Security forces say trip creates threats to buildings , bridges , tunnels along route . Environmental groups say terrorists could use chemical weapons along route in attack . Former Secret Service agent says chemical detectors could be installed along route . At inauguration , lone offenders pose greatest risk because of difficulty detecting them .