public IEnumerable<Route> GetAll(int locationId)
{
    _db.Configuration.ProxyCreationEnabled = false;
    return _db.Routes.Include(o => o.ConnectionPointRoutes.Select(s => s.Segment))
            .Include(o => o.ConnectionPointRoutes.Select(c => c.ConnectionPoint)
            .Where( c => c.Location.LocationId == locationId)).ToList();
}

public IEnumerable<Route> GetAll(int locationId)
    {
        return _db.Routes
            .Include(o => o.ConnectionPointRoutes.Select(s => s.Segment))
            .Include(o => o.ConnectionPointRoutes.Select(c => c.ConnectionPoint))
            .Where(c => c.ConnectionPointRoutes.Select(s => s.ConnectionPoint.Location)
            .FirstOrDefault(q => q.LocationId == locationId).LocationId == locationId)
            .ToList();
    }