The train operator will introduce the new scheme of'Jam' cards and 'Sunflower' lanyards to help passengers with autism, learning difficulties, and other disabilities.
The initiative being trialled by Southeastern will include the use of Sunflower lanyards and "Jam", cards which can be used by travellers to notify staff that they may need more time and support.
Southeastern, which runs train services into London from Kent and East Sussex, said staff had also received training on how best to help someone with a hidden disability.
The trial will be carried out on the operator’s Tonbridge to Hastings route before being reviewed in early 2020.
If successful, it will then be rolled out more widely across it network, which covers 540 miles of railway and 176 stations.
"Jam" or "Just A Minute" cards can be used specifically by passengers with a learning difficulty, autism or those who find it difficult to communicate to help staff understand their needs.
They can be obtained through a Southeastern ticket office or by speaking to the train operator’s customer services.
Meanwhile the Sunflower lanyard caters to a wider range of passengers with hidden disabilities such as dementia, anxiety and chronic fatigue to make staff aware they might need extra help.
However, there is no qualifying list of conditions that the initiatives apply to or to those who are able to access either a lanyard or a card.
The trial was spurred on after a member of staff, Southeastern area manager Natalie Leister, received the news earlier this year that her son had been diagnosed with autism.
“When the consultant discussed my son’s diagnosis I'll be completely honest, I cried,” she said.
“I don't know why, it was a mixture of relief but also fear - I instantly worried about what was going to happen next.
“When it came to work, his diagnosis made me question the way we look at things as employees at Southeastern.
“A school boy with autism could quite easily be misunderstood by staff who are unaware of certain behaviours.
“By providing all staff on the Tonbridge to Hastings route with additional training, and by having ‘champions’, we can ensure they are knowledgeable and aware [of] hidden disabilities.
“I’m hoping that the trial will be a huge success and we can then roll it out across the network.”
Nusrat Ghani, minister for accessibility in the Department for Transport, said: “All passengers should have equal access to our rail network and should be able to travel confidently, easily and with no extra cost.
“That’s why we are committed to ensuring support is on hand for those passengers who have additional needs.
“I welcome these latest initiatives that will help make the rail network more accessible for those with hidden disabilities.”
Previous initiatives to help people with hidden disabilities include Transport for London’s "Please offer me a seat" badges.
The scheme was launched in response to research which showed people with hidden conditions and those undergoing treatments such as chemotherapy often found it difficult to get a seat when they needed one.
Meanwhile earlier this year, the Department for Transport announced its Blue Badge parking permit scheme would be extended to people with less visible disabilities.
Officials said expanding the scheme would offer a "lifeline" to drivers or passengers with dementia, anxiety disorders or reduced mobility.