Egyszerubb.

using System;
using System.Collections.Generic;
using System.IO;
using System.Linq;

namespace ConsoleApplication1
{
    class TimesheetRow
    {
        public int Hour { get; set; }
        public int Minute { get; set; }
        public int Second { get; set; }
        public int Distance { get; set; }
        public string Origin { get; set; }
    }

    class Program
    {
        private static void Main(string[] args)
        {
            var list = new List<TimesheetRow>();

            using (var reader = new StreamReader(args[0]))
            {
                string line;
                while ((line = reader.ReadLine()) != null)
                {
                    var parts = line.Split(' ');
                    var row = new TimesheetRow
                        {
                            Hour = int.Parse(parts[0]),
                            Minute = int.Parse(parts[1]),
                            Second = int.Parse(parts[2]),
                            Distance = int.Parse(parts[3]),
                            Origin = parts[4]
                        };

                    list.Add(row);
                }
            }

            Console.WriteLine("Parsed {0} rows.", list.Count);

            var top5 = list.OrderByDescending(r => r.Distance).Take(5).ToList();

            Console.WriteLine("Top {0} rows by distance:", top5.Count);
            top5.ForEach(
                row => Console.WriteLine("{0:D2}:{1:D2}:{2:D2} {3} - {4}",
                    row.Hour, row.Minute, row.Second,
                    row.Origin, row.Distance));
        }
    }
}