For anyone expecting the US-China trade relationship to return to the halcyon days of old if the current trade conflict is scaled back, there are daily reminders that such an outcome is now impossible.

While the US Senate mulls the possibility of banning the sale of any US components to either Huawei or ZTE – bipartisan legislation for which was introduced this year – a new front in the conflict has opened up: transportation.

A bipartisan group of senators last week introduced a bill that would restrict any federal dollars from being used by transit agencies around the country to purchase rail cars or buses made by companies linked to the Chinese government.

China’s biggest rail-car manufacturer, China Railway Rolling Stock Corporation (CRRC), has made headlines in the US in recent years, snatching up contracts with municipal authorities in Chicago, Boston and Los Angeles.

The US no longer manufactures subway cars, but the authors of the legislation, including Democratic Senator Tammy Baldwin, point to China’s efforts to dominate the industry as a threat to US national security.

“China has made clear its intent to dismantle US rail-car manufacturing in its ‘Made in China 2025’ plan – our economic and national security demands that we address Chinese attempts to dominate industries that build our nation’s critical infrastructure,” Baldwin said.

Democrat Sherrod Brown, one of the bill’s co-sponsors, said: “Federal dollars should not support Chinese state-controlled enterprises that want to undermine US manufacturers and overtake our supply chain that supports rail and bus manufacturing.”

In addition to the protectionist sentiment expressed by the lawmakers, the bill cites cybersecurity as a key concern, an issue that had been raised previously when Washington, DC’s transit authority considered buying Chinese trains.