The waiting room had only two people in it. Not even a room, properly speaking: it was a large glass cubicle halfway down one of the less important platforms of a relatively unimportant station. It was nearly four o'clock on New Year's Eve: an uncertain hour on a disconcerting day, when it is easy to think back on things left undone and things which ought to have been left undone – but also an hour of uncertain hope. The pinky-blue sky of gathering dusk imbued the space with the flitting ghosts of regret, while hinting that the next day could be a new start.

The younger woman fiddled with her phone, taking a break from her serious-looking book, as if she expected the phone to give her something more tangible than a merely tentative hope. She had an unremarkable but not unattractive, twenty-something face, certainly the better for a complete lack of make-up; her skinny jeans, knitted jumper and Doc Martens were the unofficial uniform a student, her book the final confirmation. She looked up carelessly as a gust of wind blew the door open, admitting a small bird on the search for crumbs.

The older woman was a youthful forty, with the managed appearance of some sort of professional. She watched the bird for a moment, then allowed her gaze to rest on the younger woman more fully than she had before. The younger woman only looked back, for a second, when the bird suddenly flicked its wings and flew into one of the glass windowpanes with a thump. The older woman wondered why the girl had looked at her, not the bird, then noticed the poor little creature had hopped onto the row of metal chairs beside her, looking dazed. She turned swiftly and scooped the bird into her hands.

She felt it trembling under her fingers, its heart beating quickly, and stroked its wings in an attempt to calm it. She met the student's eyes, welcoming the excuse to say something, the nodded at the door. "Could you?"

The young woman was impressed with her unknown companion's deftness of action, the careful way she held the trembling bird. She noticed the woman's smart blue dress – its professional severity softened slightly by a light rose-coloured scarf – and asked herself why she found the woman's appearance and action incongruous. She jumped up. The older woman stood carefully and clicked briskly on her heels to the door, carefully releasing the bird into the open. The little creature fluttered away instantly, its accident obviously forgotten.

The student watched the older woman watching the bird, and felt an unfocused curiosity creep over her. "Well done." She liked the woman's combination of efficiency and tenderness.

The woman glanced over her shoulder, smiling slightly. "We have a cat. I rescue traumatised little birds a lot."

"Oh, I'd love a cat, but my...my circumstances won't allow it at the moment."

The woman looked at the student carefully, apparently taking in whatever her appearance said about her circumstances. "That's a shame."

"My room in halls wouldn't allow it. And my..." The girl paused, still inwardly uncertain how to refer to certain parts of her life. "My...partner's...flat is on the third floor..."

The woman nodded slowly, noticing and accepting the girl's uncertainty, then pulled a phone from her coat. "Would you like to see ours?" She was already scrolling through her images.

The student moved her bag from the seat next to her, giving the woman an excuse to sit there. Their arms touched lightly on the armrest between them as she leant in to look at the phone, and the woman flicked through a series of pictures of a large tabby looking comfortable. In some, the animal was on someone's lap. "He's definitely my wife's cat." The woman was matter-of-fact, as if her status as a spare wheel was the most important revelation.

"Oh." The student blushed with shock and a slightly sharpened curiosity, maybe also relief. She looked for a ring on the woman's long, manicured fingers. "Have you been...married long?"

The woman was about to reply when a station announcement indicated that the 16.14 via Doncaster was delayed by forty minutes. The woman tutted, the student sighed.

The woman watched the girl tuck a loose strand of hair behind her ear. "Is that your train too?"

The girl gazed at the woman's gentle hands for a moment, where they were clasped around her phone in her lap, and nodded. She was surprised to meet the woman's eye when she glanced up, and surprised when the woman held her gaze. The woman's eyes looked kind and tired, and the girl found her gaze strangely comforting rather than intrusive.

The woman tucked her phone back into her coat and nudged the girl's arm. "We seem to have some time to wait. Do you fancy a drink?"

*

In a corner of a surprisingly quiet pub near the station, the student nursed a half of cider, faintly embarrassed that the woman had paid for it; the woman sipped a glass of white wine and talked about her wife's cat. "He was a rescue kitten, two years ago." The woman looked briefly rueful. "I strayed, so she got a stray."

The girl was interested in this stranger's relationship, mainly because she was interested in the gentle and kind-seeming stranger herself. She found it easy to accept the woman's frankly-admitted unfaithfulness, and felt no real enthusiasm for knowing much about the wife as a person. "Were you together long before that?" She noticed the woman's lipstick matched her scarf. "Sorry, I'm being rude."

The woman crossed her elegant legs. Under the table, her foot brushed the girl's jeans. "Together ten years, married seven next March. My longest relationship by a long stretch. I was rather wild in my twenties." She sipped. "What about you?"

The student blushed again. She hadn't moved her leg away from the woman's foot quickly enough. "Oh, since my first year. So...two years in March?" She watched the woman watch her, and felt she ought to carry on. "She's one of my lecturers." Her hand covered her mouth as she realised her rare careless slip.

The woman's smile was reassuring, her eyes crinkled in quite an attractive way. "It's all right, I guessed. Or hoped maybe." A first little shared smile passed between them. "I'm hardly going to disapprove, am I?"

"I suppose not." The girl relaxed a little, reassured by the woman's honesty. It was as if she were being allowed to be honest herself, as if she could give voice to the feeling of inadequacy at her youth and shyness. "I...she's my first. I don't really...haven't..." She felt a conflict she'd been wrestling with for a while bubble up, suddenly find expression. "I mean, she's been good to me. She let me move in with her last year." She shifted in her seat and felt the woman's foot against her leg again. She pushed back slightly. "Her flat isn't large. I have a room in halls this year, even if I'm still more often at hers. I feel a little trapped, though. I don't know if it's me or her."

"Does one ever? Maybe it's a bit of both." The woman leant closer, her foot sliding slightly up the student's calf. "For example, I'm afraid I like meeting interesting new people, I can't help it. My wife sometimes overplays the significance of my chance encounters. Understandably." She smiled over her wine glass. "And yet here we are...", she waved a finger between them, "...talking about our partners."

The girl suspected she ought to be shocked, or at least uncomfortable, but in fact she understood. She wasn't so naïve to be unaware of her own desire to be less inexperienced, less insensitive to new possibilities and chance encounters, and she felt she could somehow empathise with this gentle, but efficient and disarmingly honest, stranger. She glanced at the woman, studying her face for a moment, and moved her leg to rest against the woman's knee. "What does a quick drink because of a delayed train signify?"

"Only what we choose to let it." The woman glanced at the clock above the bar. "Talking of quick...drink up. We should be going."

*

Although the train wasn't busy, and they might have said farewell on the platform, they somehow found it natural enough – without really speaking about it – to sit together in a virtually empty carriage. Their shoulders rested together on the mutual armrest, and it wasn't long before the girl felt the woman's leg and hip press lightly against hers.

The woman asked gently probing questions, encouraging the student to open up properly – the woman suspected, for the first time in her life – about issues which some long-term lovers never quite get round to discussing. She gave reassurance and an understanding ear, small bits of advice, some quiet sympathy. Meanwhile, she watched the girl's hand move nervously up and down on her jeans. She moved her coat across her lap so that part of it casually fell across the girl's leg and hand, and slightly altered her position in the seat.

The student felt the woman's thigh warm against her fingers, under the flap of her coat: the material of the dress, the raised edge of the hem, the smoothness of her tights. The soft, tantalising promise of comfort in another person.

The woman held her breath, smiling encouragingly when the girl hesitated a moment, and threw another question out as casually as she could. She pressed her thigh a little more firmly against the girl's hand.

The student left her hand where it was for a moment, neither moving it onto or away from the woman's leg. Instinctively, they leant slightly more into each other as they resumed the conversation, but eventually the woman shifted again, crossing her legs, and the physical contact was broken.

*

The woman excused herself at Doncaster, shrugging on her coat and wishing the girl well. The parting was genuinely good-natured, after such sharing of secrets, tinged only slightly with mutual relief that the friendship had nowhere to go.

The student was reminded of a line from something she'd been reading earlier, for an essay on short stories she was due to write: What is cowardice in the young is wisdom in the old...

*

The woman let herself into her house, finding her wife and the cat on the sofa. As she leant in to kiss her, her wife sniffed quickly. "Is that wine on your breath?"

"The train was delayed. I had a quiet little drink to pass the time."

"By yourself? We know where 'quiet little drinks' after work can lead."

"There was virtually no-one around." The evasion came easily.

*

The student wended her way through the early city-centre revellers to her lover's flat. She hadn't said when exactly she'd be back from visiting family, and knew there was bound to be some sort of party there, regardless of whether she herself was around or not – it was inconceivable for her lover to spend New Year's Eve alone.

There were four or five voices overlaying the soft music in the living room, some of which she recognised. Through the half-open door she saw her lover on the sofa, arm round a young blonde in a miniskirt. It was the pretty little first year who'd begun hanging around recently – her hand was resting casually on the lover's knee while they talked to someone out of view. One of the lover's hands held a generous glass of gin, the other played with a strand of the first-year girl's hair. The new girl looked pleased, confident; the lover looked relaxed, satisfied.

The student turned straight round and let herself out of her lover's flat unnoticed, heading for her room in halls. She felt calm, even happy for once: set free, like the little bird.