The character in Denis Johnson's "Train Dreams" exhibits the signs of aging through physical discomfort and limitations. His body is marked by various aches, such as cracking elbows and a painful, misaligned shoulder, which limit his movements and activities. Each morning presents a challenge as he struggles to ease his stiffness, revealing the toll of time on his physical condition. Despite these struggles, he pushes through the afternoons, working diligently like a well-worn engine, suggesting a relentless determination.

However, his age, now nearing forty, brings an awareness of his diminishing capabilities, especially in the woods where he once thrived. There's a poignant reflection on the inevitability of aging and its impact on one's once-reliable skills and strength. The contrast between his past vigor and present struggles highlights a sense of loss and nostalgia for better days, framed by the harsh realities of a body that can no longer keep up with the demands of his environment.